求问一道英语选择题,有关as的用法

题目

求问一道英语选择题,有关as的用法
Having never been in the country before,I was initially confused ____ the value of each coin.
A.as for B.as with C.as of D.as to
答案选的D,请问为啥啊

答案

1.这里,用法为：引出做事的依据：as to有“按照”、“根据”的含义如：①The shoes are correctly placed on the shelf as to size and colour． ②The items on the agenda are listed as to order of importance．...