When a Client Has Purchased Securities on Margin, the Broker-Dealer

When a client has purchased securities on margin, the broker-dealer

A) may require that the client leave all his securities, even those not purchased on margin, in street name.
B) must keep the securities that the client paid cash for separate from the securities that the client purchased on margin.
C) may use any securities that the client purchased on margin as collateral for a loan from a bank upon receiving a written agreement signed by the client.
D) Both B and C are correct statements.