No letter c in the big five Canadian banks. You have Scotiabank, Bank of Montreal, Canadian Imperial Bank of Commerce, Royal Bank, Toronto Dominion Bank. All spelled "Banque", as far as I know, in their French translations. (This is easy to check out on their websites but I didn't feel like looking at them all.) I've never seen it spelled Banc.

Upon reading the above posts I've decided that the system must be somehwhat different in the US than here. Still the two websites I checked out only spelled it Bank under Corporate Information.