Which of the following Articles of the Constitution of India defines for a separate secretarial staff for each House of the Parliament?

Article 98

The correct answer is Option 2 - Article 98

The Article of the Constitution of India that defines a separate secretarial staff for each House of the Parliament is Article 98.

Article 98:
Each House of Parliament shall have a separate secretarial staff: Provided that nothing in this clause shall be construed as preventing the creation of posts common to both Houses of Parliament.