The C does not have a significantly longer range than the A . It carries more fuel, but is heavier and draggier for it.
According to Jane's, the C has a radius-of-operation of 600 n miles (1,111 km; 690 miles), while that of the A is 590 n miles (1,092 km; 679 miles). If you're interested, the B's comes in at 450 n miles (833 km; 517 miles).
Both the A and C have the same payload also (8,165 kg [18,000 lb]) - it's 6,804 kg (15,000 lb) for the B, and both have the provision for six underwing stores-points.
Assuming they're ever cleared for the full envelope, then the A is cleared to +9g, while the C is cleared to +7g (+7g for the B).
The more robust landing gear etc is nice, but is the extra weight offset by any tangible operational benefit? I'm not sure that it is.
Add in the increased price tag of the C, and the only benefit that I can see Canada deriving from such a buy is the hose-and-probe refuelling system.