The ex officio Chairman of the North Eastern Council is the union Home Minister. Ex officio means by virtue of one`s position or status. In this case, the union Home Minister serves as the Chairman of the North Eastern Council automatically because of their role as the head of the Ministry of Home Affairs.

Let`s analyze the other options to understand why they are not the correct answers:

Option 1: The President of India - The President of India is the ceremonial head of the state, and while they have important roles in the functioning of the country, they are not directly involved in the day-to-day operations of the government or specific councils like the North Eastern Council.

Option 2: The Prime Minister of India - Similarly, the Prime Minister of India is the head of the government, but their responsibilities do not include being the ex officio Chairman of the North Eastern Council.

Option 4: The union Minister of State (Independent Charge), Ministry of Development of North Eastern Region - While this option mentions a specific ministry related to the development of the North Eastern region, it does not specify that this minister is automatically the Chairman of the North Eastern Council. Therefore, this option is not the correct answer.

In conclusion, the correct answer is option 3, the union Home Minister