You are a Canadian whose language is English and you don't know?
If it is necessary to talk about such things, "biracial" is an OK term.
You are rather more broad-minded than I. I think that if somebody asked me such a question I would be likely to respond with something like "What the **** do you mean?"I think mixed is the most neutral term here. People ask me all the time if my daughter is a 'mix' and I just say 'yep.'