52.
The answer is: B
Explanation
The correct option is B: President.
According to Article 310 of the Indian Constitution, every person who is a member of a defence service or of a civil service of the Union or of an all India service or holds any post connected with defence or any civil post under the Union, holds office during the pleasure of the President. This means that the President has the power to remove such persons from their office at any time without giving any reason or notice. However, this power is subject to the limitations and safeguards provided by the Constitution, such as Article 311, which protects the civil servants from arbitrary dismissal.
The Prime Minister and the Council of Ministers do not have the authority to terminate the services of the defence or civil personnel under the Union, as they are not the executive head of the Union. The President is the executive head of the Union and acts on the aid and advice of the Prime Minister and the Council of Ministers.
Therefore, option B is the correct answer.