
I got it wrong
Khan Academy's Only Chess Question?
I think it's A as well :]
(for anyone confused, heuristic means being able to find solutions quickly and effectively)
Choosing a good move to play when the computer is playing against a human is the most calculationally-intensive process and therefore most likely to be improved (quality and speed) by a heuristic. Rendering mainly involves the display, and ranking on a list requires some calculation but ultimately depends on the list itself. That's why CSV/Excel sortings are generally quick.