求解一道语法题

zhangwenteng

While digging in the Egyptian desert, huge fossil bones have been found by
paleontologists, which appears to have been the second most massive dinosaur that ever lived.

A. huge fossil bones have been found by paleontologists, which appears to have been
B. huge fossil bones have been found by paleontologists, which appear to be from
C. it appears that paleontologists have found huge fossil bones that are from
D. paleontologists have found huge fossil bones from what appears to be
E. paleontologists have found huge fossil bones, which are from what appear to be

pls give reasoning between D and E

答案：D

D 中为什么用APPEARS 啊？？ BONES 不是复数吗?

janeeee

D选项：huge fossil bones
        from what appears to be the second most massive dinosaur that ever lived.

what引导一个名词性短语，dinosaur是单数，指代它的what当然也是单数，所以用appears！