That's a legitimately good question, and you should feel bad for not knowing how to answer it.
My answer to that question would be, "I will be very happy to. My rates as a management consultant are $X per day." :-)
Just saying you don't have enough information to formulate a plausible response doesn't make a very good impression from my experience.
They're asking you to qualify yourself and so you need to know where you fit into the equation.
Note that he does not say that he was unable to answer the question. That is a conclusion you jumped to.
For all we know it could mean "hey, for an interview exercise, I'd like you to sell (this guy) on the importance of automated testing."
Suddenly it sounds like a pretty good interview question.
You should feel bad for being one of those who would end up dragging interview process to hell.