In Connection with a Checking Account at a Bank,what Is

In connection with a checking account at a bank,what is an overdraft?

A) a check that the bank does not pay, due to insufficient funds in the account
B) a negative balance caused by a bank paying a check when there are insufficient funds in the drawer's checking account
C) a post-dated check for a larger amount than the drawer's checking account balance
D) any kind of loan at a bank where a customer also has a checking account
E) a deposit by a customer that is later returned because of insufficient funds