The correct answer is option 3, 97 subjects. The Union List in the Indian Constitution is a list of subjects on which only the central government has the power to make laws. These subjects include areas like defense, foreign affairs, banking, atomic energy, and telecommunications. The Union List is mentioned in the Seventh Schedule of the Indian Constitution, and it consists of a total of 97 subjects. It is important to note that the Union List is one of the three lists in the Seventh Schedule, with the other two being the State List and the Concurrent List. The State List includes subjects on which only the state governments have the power to make laws, while the Concurrent List includes subjects on which both the central government and the state governments can make laws.