Why do people hold money (currency and checking account balances), and thereby forgo earning interest or dividends from a financial investment?

a. Some money is demanded for everyday transactions like parking fees, lunch, and buying groceries.
b. Some money is demanded as a precaution against unexpected costs such as automobile repairs, speeding tickets, or temporary loss of a job.
c. Some money is demanded for speculative purchases of stocks, bonds, or collectibles in case they become available at a particularly low price.
d. All of the above are correct.

d