أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
THE PERSON WHO ANSWERED FRANKLY THAT HE DOES'NT KNOW THE ANSWER IS THE BEST ONE.
Better to admit that you don't know the answer in this way. Its a good question, but I'm sorry, I don't have the answer in your question.
In this situation the best way is say the truth instead of acting like "I know the answer".