I think the answer is C.

You need that following indicates, so you can immediately eliminate D and E. A and B are both awkward with the ratio phrasing.

Although their in C is somewhat ambiguous, so now I'm second guessing myself.

IMO "C". Probably CEO's should be CEOs.

A recent review of pay scales indicates that CEO’s now earn an average of 419 times more pay than blue-collar workers, compared to a ratio of 42 times in 1980.
A. that CEO’s now earn an average of 419 times more pay than blue-collar workers, compared to a ratio of 42 times
>> ratio and times together not correct.

B. that, on average, CEO’s now earn 419 times the pay of blue-collar workers, a ratio that compares to 42 times
>> "compares" should be compared. Also same issue as of "A".

C. that, on average, CEO’s now earn 419 times the pay of blue-collar workers, as compared to 42 times their pay, the ratio
>> correct

D. CEO’s who now earn on average 419 times more pay than blue-collar workers, as compared to 42 times their pay, the ratio
>> who is incorrect. "that" missing

E. CEO’s now earning an average of 419 times the pay of blue-collar workers, compared to the ratio of 42 times
>> earning is not correct....should be earns. "that" missing.

I think B.

In C, "their" is not clear as to who it indicates...

OA pls

OA: C (GMAT prep)