Who is authorised to make rules and regulations regarding the number of members in the Union Public Service Commission?

Correct option is A

The correct answer is a) President of India.
According to Article 318 of the Indian Constitution, the President is empowered to determine the number of members of the Union Public Service Commission (UPSC) and their conditions of service.

Information Booster :

Constitutional Framework for UPSC
The UPSC is an independent constitutional body established under Article 315. However, the Constitution does not fix the exact strength of the Commission. Instead, it leaves this detail to the discretion of the executive head.

Determining Composition: The President makes regulations to decide the number of members. Typically, the Commission consists of a Chairman and 9 to 11 members.

Appointment: Under Article 316, the Chairman and other members are appointed by the President.

Conditions of Service: The President also frames rules regarding their tenure, salary, and allowances. To ensure the independence of the UPSC, the Constitution stipulates that these conditions cannot be varied to their disadvantage after appointment.