B.
英语习惯,无论疑问句是肯定还是否定,反义疑问句前半部是肯定还是否定,只要否定回答都用no,这句话完整的回答是：
No,I haven't been around much lately; I've been away on vacation.
省略了 I haven't been around much lately
否定疑问句或反义疑问句前半部是否定时和中文习惯刚好相反,例如
Aren't you from Shanghai?你不是上海人吗?
No,I am not.是,我不是上海人.
Yes,I am.不,我是上海人.