Explanation:

- Option 1: 3 years

Not suitable for Senior Citizen Savings Scheme. Typically, schemes with this duration are for moderate-term savings.

- Option 2: 5 years

This is the correct option. The Senior Citizen Savings Scheme (SCSS) has a maturity period of 5 years. It is designed to provide senior citizens with a secure and steady income post-retirement.

- Option 3: 2 years

Too short for SCSS. Such durations are often used for recurring deposits or short-term fixed deposits.

- Option 4: 7 years

Longer than necessary for SCSS. Often associated with long-term deposits or savings options.

- Option 5: 4 years

Another moderate duration, but not used for SCSS.