Explanation:

- Reserve Capital: This is the part of a company’s uncalled capital that can only be called up in the event of liquidation. It's a safeguard for creditors, ensuring that the company has additional funds available if needed.

- Paid-up Capital: The actual capital paid by shareholders. It's funds the company has received in exchange for shares issued.

- Forfeited Share Capital: This represents shares that were originally issued but later forfeited due to non-payment by shareholders when calls on shares were made.

- Assets: Items of value owned by the company. Reserve capital is not an asset, but rather a portion of the uncalled share capital.

- Correct Answer: Option 4 - Capital to be called up only on liquidation of company