Sentence Correction

829. The speculative fever of the Roaring Twenties infected rich and poor alike; vast quantities of people were dangerously overextended, credit was absurdly easy to obtain, and most brokerage houses required only ten percent cash for stocks bought on “margin.”
(A) rich and poor alike; vast quantities of people were dangerously overextended
(B) both rich and poor alike; large amounts of people dangerously overextended themselves
(C) rich and poor alike; great numbers of people were dangerously overextended
(D) both rich and poor alike; vast amounts of people dangerously overextended themselves
(E) both rich and poor; great quantities of people were dangerously overextended

Hi,
The only difference I see between C) and E) is "alike" after poor and rich. Is it necesarry? The answer is C).