I have the information句子完整,不需要what引导的从句,但是加了of之后,需要有of后面的东西,所以选A
He made a promise that if anyone set him free he would make him very rich.从句子意思看的,如果有人放了他她就会给那人好多好多钞票.不过我感觉的A也可以,但是如果是A的话,He made a promise that anyone set him free ,he would make him very rich.句子要断一下,我改的不太好,但句子要改动一些.考试不会考的,你选that的话,外国人也懂