Explanation:

- Option 1: 2 years – The tenure of the SEBI Chairman is not fixed at 2 years.

- Option 2: 3 years – This is the most common initial appointment duration for the SEBI Chairman. They are typically appointed for 3 years, and the appointment may be extended.

- Option 3: Not Fixed – The tenure is not "not fixed." Legally, it's generally for 3 years, subject to reappointment, up to an upper age limit.

- Option 4: None of the above – This option is incorrect because Option 2 is right.

Correct Answer: Option 2, 3 years.