Well, technically it would be 11, but if you are just looking for -|-11|, it would be -11, but you asked for the absolute value of -|-11| and -|-11| = -11, so then the absolute value of that would look like |-11|, and the answer to that would be 11.
I thought the same, actually. The correct interpretation is \(|-|-11||\), but I feel as if this is not what the guest meant.