Explanation:

- Fiat Money (Option 3): This is money that has no intrinsic value and isn't backed by a physical commodity. Its value comes from being declared legal tender by a government.

- Legal Tender (Option 2): This term refers to money that must be accepted if offered in payment of a debt. By law, it is recognized as a valid form of payment.

- Flat Money (Option 1): This is incorrect. It appears to be a misspelling or misunderstanding. The correct term is "Fiat Money".

Correct Answer: Option 4 - Both b and c

Currency notes and coins are both legal tenders and fiat money. .