Zero Settlement Balance Requirement by the Chartered Banks in Canada

Zero settlement balance requirement by the chartered banks in Canada implies all of the following except one, which is:

A) if the chartered bank's deposit account with the Bank of Canada is overdrawn at the end of day's banking transactions, it must borrow to cover the overdraft, either from another bank of from the Bank of Canada.
B) falling short of the zero balance imposes a cost on a bank.
C) positive settlement balance by a bank has zero opportunity costs.
D) with a negative balance, the chartered bank can borrow from the Bank of Canada at the bank rate.