Option 1: Both A and R are individually true and R is the correct explanation of A.
Option 2: Both A and R are individually true, but R is not the correct explanation of A.
Option 3: A is true, but R is false.
Option 4: A is false, but R is true.
The correct answer is option 4 - A is false, but R is true.
Explanation: The reason provided in option R is correct. The Union Public Service Commission (UPSC) was indeed constituted under the provisions in the Constitution of India. However, the assertion in option A is incorrect. The number of members of the UPSC is not prescribed in the Constitution of India. The number of members of the UPSC, including the Chairman and other members, is determined by the President of India. The Constitution provides a framework for the establishment and functioning of the UPSC, but it does not specify the exact number of members. Therefore, while the reason is true, the assertion is false, making option 4 the correct answer.