Explanation:

- Option 1: Legacies are typically not treated as a liability. Liabilities represent obligations, whereas legacies are a form of receipt.

- Option 2: Legacies, often received as a gift or bequest, should be considered a capital receipt rather than a revenue receipt, making this option somewhat inaccurate in standard accounting.

- Option 3: Legacies can be treated as an income in the sense of being part of capital receipts, although they are not considered regular operational income.

- Option 4: None of these might be seen as fitting if none of the other descriptions perfectly align in the context.