The Main Reason Banks Are Prohibited from Investing Deposits in Common

The main reason banks are prohibited from investing deposits in common stocks is that

A) the federal government does not want banks to provide competition for stockbrokers.
B) worrying about fluctuations in stock prices might distract bank managers from their other activities.
C) the existence of deposit insurance gives bank managers an incentive to make risky investments.
D) common stocks are not very liquid investments.