When the Bank of Canada Buys a Canadian Bond in the Open

When the Bank of Canada buys a Canadian bond in the open market

A) it has no effect on the total reserves or the money supply because the cheque it writes increases reserves at one bank but they fall at another.
B) total reserves increase by the amount of the purchase but the money supply stays the same.
C) it expands total reserves and the money supply.
D) it contracts total reserves and the money supply.