While digging at an oasis in the Egyptian desert,
paleontologists found huge fossil bones from what appear to be the second most massive dinosaur to ever live. (A) paleontologists found huge fossil bones from what appear to be the second most massive dinosaur to ever live
(B) paleontologists found huge fossil bones from what appear to be the second most massive dinosaur ever living
(C) paleontologists found huge fossil bones from what appears to be the second most massive dinosaur that ever lived
(D) huge fossil bones have been found by paleontologists, which appear to be from the second most massive dinosaur ever living
(E) huge fossil bones were found from what appear to paleontologists to be the second most massive dinosaur that ever lived
Solution:
Confused between A & C: appear or appears?
Here the dinosaur whose fossil bones were discovered is compared with rest other dinosaurs known till now and after comparing, the sentence tells that, the dinosaur whose fossil bones were discovered appears to be the second most massive dinosaur.
Other way could be: from what, tells us about the entire scenario or a picture of huge fossil bones as a whole, and this scenario or picture seems to be singular and so appears is preferred to appear.