Option 1 states that both statements are individually true and that Statement II is the correct explanation of Statement I. To analyze this option, let`s break down each statement.

Statement I: In the year 1946, the Council of the Muslim League accepted the Cabinet Mission Plan. This statement is generally accepted to be true. The Cabinet Mission Plan was proposed by the British Government in 1946 and was accepted by the Muslim League.

Statement II: The Muslim League proposed to join the Interim Government. This statement is also generally accepted to be true. The Muslim League did propose to join the Interim Government that was being formed during the transition to Indian independence.

Option 1 claims that Statement II is the correct explanation of Statement I. However, this is not entirely accurate. Even though both statements are true, they are not directly related. The acceptance of the Cabinet Mission Plan by the Muslim League does not automatically imply their proposal to join the Interim Government.

Therefore, Option 2 is the correct choice. Both statements are individually true, but Statement II is not the correct explanation of Statement I. It is important to analyze the statements separately and not assume a cause-and-effect relationship between them.