I would simple plead the Fifth if that is possible. I would not answer the questions as they are a trap not a legit attempt to enforce civil law. "I do not remember", "I do not recall" or "I do not know about that," could entrap him if there are emails or text messages or a corrupt former attorney sitting in jail willing to lie to get out. Even if something occurred 10 years ago and Trump really does not remember the details, a email or letter from ten years ago could entrap him.
“The fact that she has made the accusation of criminal misconduct would lead me to believe the civil case is a pretense . . . “
The civil case is a fishing expedition to find evidence to bring criminal charges. A case searching for a crime. It demonstrates how thoroughly corrupt the “justice” system has become.