As Esquilax says, A is definitely not a win-win option. We need to think of the big picture as well. We didn't come to Tjaru or to Egypt with the aim of taking out this Lord Marduk at whatever cost. Now, someone who is our enemy comes along and suggests "hey trust me let's go kill Marduk by putting you in the riskiest position evar" and we're going to say yes? All the work we did to turn Egypt into a country that will hopefully support us, a place from which to draw on for manpower and resources, and ideally to then use as a jump-off point for traveling/conquest or to leave a legacy for later - we're giving up on all the good work we did in Egypt and Tjaru for a sudden, ill-defined assassination quest that squarely puts us at the mercies of a devious, mind-controlling Gieloth.
I don't think that anyone expected a lot of things in Egypt - we've definitely strayed from our goal of "kill remaining Children of Sekhenun, install pharoah, then gtfo!" The world is interconnected, and the decisions that we make in Egypt caught the attention of the outside world. But I agree that there comes a time when you've got to say "enough is enough" and stop reacting to your opponent's moves so that you can make some of your own.
What concerns me is this:
if Nabu has a device that amplifies his psychic abilities, why would he dismantle it once we agreed to his arrangement? Why would Nabu get rid of the one thing that's keeping us from killing him? It doesn't add up, it's like a bully no longer robbing you because you pay him. Sure, maybe he needs our mind sharp so that we can kill Marduk for him, but why would he let us recover during the journey and hope we don't kill him along the way? It doesn't make sense for a manipulator to expose himself like that. It's just as likely that he's a loyal soldier to Marduk - after all he saved Baran with his psychic shield, and from all appearances Baran was quite loyal.
Proximity plays a big role in Nabu's power because it's a factor in Ean's own telepathy/psionics. Ean can't scramble someone's brain or read their thoughts without touching them, so how close/far we are from Nabu certainly matters a great deal. Nabu could easily destroy our mind with his tower up close - but with the Honorblade, our defenses up and our distance from the attacker, it might be just enough to stay alive.
I think that it is worth the risk and that we have a chance at pulling through.
FLOPPING TO C. What clinched it is that I realized that all of the options but D are all equally risky. Option A could simply be an ploy designed to draw us out and fry our minds. Option B is just plain crazy.
But C is the only one that allows us to keep things on our own terms. The battle is taking a heavy toll on the attackers, and I am hoping that this is a ploy by Nabu to try and end the battle quickly.
Edit:
Zero Credibility: A page or so ago, you corrected me by saying that the worst-case scenario for C was being put into a coma and captured once our men are slaughtered. Well, that's also true for A/B, except for those two options we pretty much gift-wrap our body for the Gieloth's convenience. With C, at least we can hold out for some hope that our men will retreat back to the Delta with our body in tow. There is at least the chance of escaping should things go sour, while A/B don't offer even that.
...it's also an option to keep the story grounded in human affairs and us as champions of humanity, making for more interesting options. Nothing awaits us in Sumeria except for Gieloth power politics and shadowy sneaking around that we have always sucked at. Egypt is where we can make a name, where we can raise an army, where we can lead them to glory against Sumeria or otherwise.
We're about fifty updates in and we still have no clue what this galactic conflict is about. Being a champion of humanity is all well and good, but we have to know what the fuck is going on at some point. Playing Gieloth power politics is probably not the way of going about it; our guy isn't some Sumerian Anthony Sommers here, he sucks at this sort of thing. Astarth is a mortal and he played us like a fiddle, how do you imagine we'll fare against beings like that, except now they've got superpowers?
I've already mentioned Astarth's army before as a potential distraction, but I'm not sure anymore. Astarth's men are all the way in Thebes, it would take them a long time to reach Babylon. Assuming it isn't a trap, we'd probably be seeing Marduk long before they show up.