The highest body that approves the Five-Year Plan in India is option 2, the National Development Council.

Option 1, the Planning Commission, is incorrect because the Planning Commission played a significant role in India`s economic planning until it was abolished in 2014. It used to be responsible for formulating and implementing the Five-Year Plans, but it did not have the authority to approve them.

Option 3, the Finance Ministry, is incorrect because while the Finance Ministry may have an important role in the economic planning process, it does not have the authority to approve the Five-Year Plans. Its main responsibility is to manage the country`s finances and provide financial advice to the government.

Option 4, the Union Cabinet, is also incorrect because although the Cabinet may discuss and provide inputs on the Five-Year Plans, it does not have the ultimate authority to approve them. The National Development Council, which is a separate body, holds the final power to approve these plans.

Therefore, the correct answer is option 2, the National Development Council, as it is the highest body that approves the Five-Year Plans in India.