Martha sets her jaw, though it's more to keep her teeth from audibly chattering than it is to keep from answering the questions he asks. Though she's not very willing to do that either. Not in front of everyone watching. This is an ancient time compared to hers, and she does not want to misstep any further than she may have only to end up dead. She can't stop from visibly shivering though. Martha was not dressed for this land. Especially with winter coming. At the very least she can offer the name of her city. It likely won't mean anything.

"L-London," she replies, the cold causing her to stutter. "I'm from a city called London." She ignores the question of the TARDIS.