Explanation:

- Social security in India is provided through various schemes and instruments aimed at ensuring financial stability.

- 1. Income Tax

- Not a social security instrument; it's a government revenue collection tool.

- 2. Employees' Provident Fund

- This is a key social security measure providing retirement savings.

- 3. General Sales Tax

- Also not a social security instrument, it's another form of tax revenue.

- 4. LIC (Life Insurance Corporation)

- Provides financial security through insurance policies.

- 5. National Pension Scheme

- A government-initiated pension scheme providing retirement security.

- 6. Postal Provident Fund

- Offers savings and investment for long-term financial security.

The correct option is Option 3: 2, 4, 5 and 6.