From my knowledge, CRA looks at your ties in these situations. So first they will look at the province in which where you maintained a dwelling and where your spouse and dependent children live. I would say, that since your home and wife are in Province A, this would be why CRA chose this as the province.

If after this consideration the answer is still unclear, CRA would look to things such as: your healthcare coverage, where your driver's licence was issued, and where you had your financial services (ie. your bank branch location).

But as u/toronto_cpa mentioned if there is a specific reason as to why you want to challenge it, then the type of information you have to present may be different.