Choose the correct sentence.
in an area devoid of volcanic activity:

a. discovery has been made by a team of scientists from the university of california that a fragment of the swiss alps seems like it came from a depth as far down as 415 miles.
b. discovery was made by a team of scientists from the university of california who found a fragment of the swiss alps that seems like it had come from a depth of as much as 415 miles.
c. team of scientists from the university of california have discovered a fragment of the swiss alps that has seemingly come from a depth of as great as 415 miles.
d. team of scientists from the university of california has discovered a fragment of the swiss alps that seems to have come from a depth as great as 415 miles.
e. team of scientists from the university of california has made the discovery of a fragment of the swiss alps that had seemingly come from a depth as far as 415 miles.