how much are these books cost 是个什么啊?进来看看,上次提了一次,但又有一个问题

how much are these books cost 是个什么啊?进来看看,上次提了一次,但又有一个问题
I wonder____
A.how much cost these books
B how much do these books cost
C how much are these books cost
D how much these books cost
求大家能回答完整点 much are these books cost 这是一个倒装句吗?是疑问句?还是倒装的疑问句,麻烦看看下面的例子
我觉得从下面的例子中看出来how many people there are 是一个倒装句,是有关于there be 的完全倒装 (请问它还是疑问句吗?) 所以我觉得上面的句子how much are these books cost 不是倒装,那为什么不能选呢?
Have you investigated ____ in scientific locations?
A.are there many people
B how many people are there
C how many people there are
D.that there are how many people
这题是选C