Which of the following illustrates the store$-$of$-$value function of money?

keeping $$20,000$ in cash in your mattress instead of buying a new Volkswagen

writing a check to buy a new Volkswagen

noting that the price of a $$20,000$ Volkswagen is $16,000$ euros

agreeing to repay a bank $$400$ a month for the next $48$ months for a loan to buy a new Volkswagen