The correct answer is option 2: The Prime Minister of India. The ex-officio Chairman of the Planning Commission of India is the Prime Minister.
Let`s dissect the other options for better understanding:
Option 1: Vice-President of India - The Vice-President of India does not hold the position of the ex-officio Chairman of the Planning Commission.
Option 3: The Finance Minister of India - While the Finance Minister plays an important role in economic planning and budgeting, they do not automatically become the Chairman of the Planning Commission.
Option 4: The Law Minister of India - The Law Minister`s primary responsibility is related to legal matters and governance, and they do not hold the position of the Chairman of the Planning Commission.
Therefore, option 2, the Prime Minister of India, is the correct answer as they hold the position of the ex-officio Chairman of the Planning Commission.