---You were brave enough to raise objection at&n

---You were brave enough to raise objection at the meeting.---Well, now I regret _______ that.A.to doB.to be doingC.to have doneD.having done

D解析regret doing sth 表示对已经发生的事感到“后悔”；regret to say / tell / inform / announce 用以报告令人不快之事，表示对将要说的话感到“遗憾、抱歉”，主语通常是 I / we, regret 用一般现在时。

回答的不错