Which of the following most logically completes the argument?
Yorco and Zortech are two corporations that employ large numbers of full-time workers who are paid by the hour. Publicly available records indicate that Yorco employs roughly the same number of such hourly wage workers as Zortech does but spends a far higher total sum per year on wages for such workers. Therefore, hourly wages must be higher, on average, at Yorco than at Zortech, since _____.

A. Zortech spends a higher total sum per year than Yorco does to provide its hourly wage workers with benefits other than wages
B. the work performed by hourly wage workers at Zortech does not require a significantly higher level of skill than the work performed by hourly wage workers at Yorco does
C. the proportion of all company employees who are hourly wage workers is significantly greater at Yorco than it is at Zortech
D. overtime work, which is paid at a substantially higher rate than work done during the regular work week, is rare at both Yorco and Zortech
E. the highest hourly wages paid at Yorco are higher than the highest hourly wages paid at Zortech

I'll second that (B). Roughly the same number of workers that happen to be paid at different hourly rates (beased on a higher skill base) equals a higher overall annual salary expenditure at Yorco.

I go for C

Surprisingly everybody got it wrong OA is D

(A)Zortech spends a higher total sum per year than Yorco does to provide its hourly wage workers with benefits other than wages
non-wage benefits has nothing to do with wages
Wrong

(B)the work performed by hourly wage workers at Zortech does not require a significantly higher level of skill than the work performed by hourly wage workers at Yorco does
Doesn't follow the comparison laid out in the question. It is perfectly possible that Z has easier jobs but still higher wages
Wrong

(C)the proportion of all company employees who are hourly wage workers is significantly greater at Yorco than it is at Zortech
Contraditary with info already provided
Wrong

(D)overtime work, which is paid at a substantially higher rate than work done during the regular work week, is rare at both Yorco and Zortech
Correct. If over time is not rare in Y but rare in Z, then it might be a reason why Y spends more money than Z, even if Y's average wage is not higher than Z. Getting rid of this probability will be able to support the conclusion arrived in the last sentence of the opening question

(E)the highest hourly wages paid at Yorco are higher than the highest hourly wages paid at Zortech
Highest wage says nothing about average wages
Wrong