Option D is Correct

The Administrative cadre comprises the most senior civil servants who organize and coordinate the activities of the ministries. They execute high-level administrative work, advise ministers in the formulation and implementation of policies and serve as the communication link between the minister and other civil servants.
Recruitment to this class is based on university education and very competitive written examinations and interviews conducted by the civil service commission. In this class are directors-general, other directors, deputy directors, assistant directors, etc.