Explanation:

- Loan from financial institutions: Borrowed funds obtained from banks or other financial organizations. Companies repay with interest over time.

- Debentures: These are debt instruments that companies use to raise long-term finance from public investors. Investors receive interest, but no ownership stake.

- Retained earnings: Profit that a company keeps in reserves instead of distributing as dividends. This is an internal source of funds, not borrowed.

- Public deposits: Funds raised directly from the public. Companies offer interest and use these funds for business operations.

Correct Answer: Option 3 - Retained earnings