The temperature differences seen between seattle, washington, and spokane, washington, illustrate the effect of a. geographic position b. ocean currents c. cloud cover d. altitude

The answer is A. geographic position.

Temperature is one of the determiner of weather of a place. One thing that affect the weather is the geography of an area. The geographical position of a particular area includes the topography (features of an area such as mountains, rivers), latitudes that impact the intensity of the sun light, vegetation cover, human impact on the land.