Without a reference point, this table only gives you the brokerage differentials. Using Bank Of Canada noon rates for this day yields a true cost of $20,079 for the $15K CAD. Lots of people know you can use Norbert's Gambit to minimize currency conversion, with a fee of about 20 bps (0.20%) or $40 including commissions.

So the "best", though more complex option would make the total $20,120 for the wholesale rate, or $180 less than the average shown in the table. With the Scotia US Friendly, don't forget the $120 annual fee to get this deal.