The correct answer is option-1, the Prime Minister. The National Disaster Management Authority (NDMA) is the apex body responsible for coordinating and implementing disaster management policies and measures in India. It was established in 2005 and operates under the Ministry of Home Affairs. The NDMA is headed by the Prime Minister of India, who serves as the Chairman of the Authority.
Option-2, the Home Minister, is not the correct answer. While the Ministry of Home Affairs oversees the functioning of the NDMA, the Authority is not directly headed by the Home Minister.
Option-3, the President, is also not the correct answer. The President of India is not directly involved in the day-to-day operations of the NDMA.
Option-4, the Health Minister, is not the correct answer either. While the Health Minister plays a crucial role in disaster management, they are not the head of the NDMA.
In conclusion, the Prime Minister holds the position of the Chairman and is the top authority in the National Disaster Management Authority.