A recent national study of the public schools shows that there are now one microcomputer for every
thirty-two pupils, four times as many than there were four years ago.
(A) there are now one microcomputer for every thirty-two pupils, four times as many than there were
(B) there is now one microcomputer for every thirty-two pupils, four times as many than there were
(C) there is now one microcomputer for every thirty-two pupils, four times as many as there were
(D) every thirty-two pupils now have one microcomputer, four times as many than there were
(E) every thirty-two pupils now has one microcomputer, four times as many as

answer is C
pls explain