选C.
根据she's never been to Hong Kong中she's,判断该句助动词为has,所以排除A/B.
反义疑问句中,陈述句肯定,附加问句用否定;陈述句否定,附加问句通常用肯定.根据这一规则,C/D均可.
下文语境but now she wishes to go there again可知,she曾去过hongkong,所以第二说话者要先答：yes,she has been to hongkong.缩写成yes