Select the correct statements about margin accounts.

1.Margin calls must be paid without delay.

2.Margin increases market risk.

3.The dealer can only sell securities from the account with the client's consent.

4.Loan interest must be repaid by the client to the dealer.

a.1 and 2

b.1 and 3

c.1,2,3 and 4

d.1,2 and 4