Answer : 4. "All of the above "
Explanation :

The following are required to file income tax return online:

PAN Card: It is a mandatory document that authenticates you as identity and address proof for filing income tax returns.

Aadhaar Card: This is an optional document that can be used as identity proof.

Form 16: This is a certificate that shows your income and deductions. Your employer provides you with Form 16.

Bank account details: You will use your bank account to pay your return.

Copy of previous year's return: A copy of the previous year's return is also required.

Internet Connection: You will need an internet connection to file your return on the Income Tax Department website.