Which amendment restricted the size of Council of Minister to 15% of the total size of the house?

91st

The correct answer is Option 3 - 91st

The amendment that restricted the size of the Council of Ministers to 15% of the total size of the house was the 91st Amendment Act of 2003.

This amendment modified Article 75(1A) of the Indian Constitution, placing a cap on the number of ministers, including the Prime Minister, that can be part of the Council of Ministers.