A.动词wonder后跟的是一个宾语从句,整个宾语从句是一个强调句,强调的是句子的主语---**;从句部分为it is ** that makes him so excited.如果就**提问的话,应该用what；what is it that makes him so excited.整个句子是宾语从句,所以应用陈述语序,what it is that makes him so excited.