This was unexpected, but because it occurred during office hours, I was already in question-answering mode.
I replied, "I'm not allowed to tell anyone under 30."
"Wow, that's the best answer I've ever heard!"
Of course if you come ask me the answer to a homework problem I'm not going to tell you. But I am generally happy to answer questions about anything. As you see, my evasion skills are advanced.
This post's theme word is ineluctable, "impossible to avoid." Outside of law courts, there are no ineluctable questions.