Meaning of 返答 in Japanese

彼の返答は拒絶も同然だ。
His answer amounts to a refusal.

その学生に、学校へはきちんと通っているのかと聞いたら、返答に詰まってしまった。
When I asked the college student if he regularly attended his school, he was at a loss for an answer.

私は返答に窮した。
I was at a loss for an answer.