Why Was Changing of Reserve Requirements Phased Out as a Tool

Why was changing of reserve requirements phased out as a tool used by the Bank of Canada to control the money supply?

A) to make the rules the same for all financial institutions since only credit unions were required to hold reserves
B) to make the rules the same for all financial institutions since only commercial banks were required to hold reserves
C) because Canada was the only country still imposing reserve requirements on its financial institutions
D) because the Bank of Canada was using it too frequently, causing disruption in the banks