Beta Enterprises has been accused of age discrimination in its hiring process, as most of the employees recently recruited are below 35 years of age. The management of the company denies this allegation. Beta could best defend itself against the charge by showing that—

The allegation is that Beta Enterprises discriminates based on age, preferring younger applicants.
To counter this, the company needs to prove that age was not the deciding factor — instead, the selections were made on the basis of merit or qualifications. Option C shows exactly that: the older applicants were rejected because they failed the skill assessment test, not because of their age.
This directly weakens the discrimination charge. Hence, C is the correct answer.