Final answer:
Orographic precipitation is the most important factor in the remarkable spatial variation in precipitation in British Columbia.
Step-by-step explanation:
The most important factor in the remarkable spatial variation in precipitation in British Columbia is orographic precipitation. Orographic precipitation occurs when moist air is forced to rise over mountains, resulting in increased precipitation on the windward side and decreased precipitation on the leeward side. In British Columbia, the presence of the coastal mountain ranges contributes to this phenomenon, creating distinct precipitation patterns across the region.
The other factors mentioned, such as population distribution, ocean currents, and the pineapple express, may also influence local precipitation to some extent, but orographic precipitation is the primary driver of the remarkable spatial variation in precipitation in British Columbia.