Tony is __ the guidebook ,looking for information about Japa

Tony is __ the guidebook ,looking for information about Japan ,__he will travel soon.
A looking into ;where B going through; where C looking up ,which D referring to;which
求详细解析

选B.go through 是浏览的意思,refer to 是查找（字典）的意思,比如refer to the dictionary,look up 是查找字典）的意思,比如look up the word in the dictionary,look into有调查,研究的意思.
第二个空,是非限制性定语从句,如果用which的话,之前要用to ,就是to which ,因为这样才能构成完整词组travel to Japan,而且where,when 等疑问词等价于prep（介词）+which/who/whom
最后,整句话的意思是：tony正在浏览旅游指南,寻找有关他将要去的日本的信息.