Lenders cannot require debt to be repaid in gold or wheat - they have to accept money. This is because money is:

divisible.

made out of paper.

a medium of exchange.

legal tender.

The price level tends increase over time, therefore it follows that:

money is a good medium of exchange.

money (currency and checkable deposits) is the most liquid part of the money supply.

money is an imperfect store of value.

All of the answers are correct.