Explanation:

- Non-Performing Assets (NPAs) are loans or advances for which the principal or interest payment remains overdue.

- The correct criterion is more than 90 days without payment, which typically classifies an asset as non-performing.

- During these 90 days, the asset does not generate income for the bank.

- This timeline is widely acknowledged as the standard across most banking regulations.

Correct Answer: Option 3 - 90 days