According to the Indian Constitution, the correct answer is option 1 - President of India. The Constitution grants the President the power to appoint and remove Ministers from office. The Ministers serve at the pleasure of the President, which means they can be removed by the President at any time. This provision ensures that the President, as the head of state, has control over the executive branch and can hold the Ministers accountable for their actions. It also allows the President to maintain the stability and efficiency of the government by removing Ministers who are not performing their duties effectively or are involved in any misconduct. Therefore, the Ministers in the Indian government hold office at the pleasure of the President.