Under a 401(k)plan,what Is Compared to Determine If the Plan

Under a 401(k) plan,what is compared to determine if the plan unfairly discriminates in favor of highly compensated employees?

A) the average percentage of salary made available to the highly compensated to defer is compared to the average percentage of salary made available to other eligible employees to defer
B) the ratio of eligible highly compensated employees is compared to the ratio of eligible other employees
C) the average percentage of salary deferred by the highly compensated is compared to the average percentage of salary deferred by other eligible employees
D) the percentage of highly compensated employees over age 50 who participate is compared to the percentage of all other employees who participate