答案C
解析:表示道歉的常用语有:Excuse me(for…)/I'm sorry./I hope you'll excuse me./I beg your pardon./I must apologize.等等。应答语有:It doesn't matter(at all)./It's nothing./Not at all./That's(quite)all right(OK)./Please don't worry about that./Never mind about that. /Please think nothing of it./Let's forget it./No problem.等等。
拓展延伸:在需要打扰或冒犯对方时,常用Excuse me. 当自己有过错需要对方原谅时,可用Excuse me(for…)或I'm sorry…但在某些场合你并没有过错时,要慎用I'm sorry,以免承担不应承担的责任。