I doubt she'd have wasted a question on Thom, given what she already had to go on, and the other urgent issues facing her. She might have been told about the Waste and Rhuidean, given her reaction to Rand's decision to go there, and the Wise Ones' revelation that in all the alternate timelines she had been the one to bring up the subject of her tersting, thus implying she learned of the necessity from another source. Furthermore, she might have a good poker-face (though not so much as is generally implied by her rather unsophisticated observers, in fact she reacts to surprises very often, if only with some sort of facial or verbal slight of hand to disguise her ignorance), but she was a little TOO calm about Melaine's slip. Usually that would have been good for an eyebrow quirk at the least.

She might have asked how she can best protect and guide Rand and been told to go through the rings in Rhuidean. Given what she says (and therefore believes) of the constraints on asking questions touching the Shadow (and by extension, most questions concerning the Dragon Reborn, in her mind), or asking questions that do not concern the asker, I think it safe to say that the confluence of her priorities and perceived limitations, that would be the most likely quesiton.
- Asking how Rand can win or what he should would not concern her, and would almost certainly touch on the Shadow
- Asking what she should have Rand do is essentially the same thing, and a bit limited as well. She would (or at least SHould) have been looking at the big picture, rather than the immediate crisis.
- If she had to ask about herself, asking what she could or should do concerning Rand is the best bet. The Wise Ones claim that if she did not go through the rings Rand would die. Therefore, going through the rings is the best thing she could for/about Rand. QED.