Although Oregon and South Dakota Are at Similar Latitudes, Winters

Although Oregon and South Dakota are at similar latitudes, winters in Oregon arewarmer and summers in Oregon are cooler. Which of the following might explain these differences between the climate of Oregon and the climate of South Dakota?

A) South Dakota has fewer trees.
B) The Pacific Ocean makes Oregon temperatures more moderate.
C) Oregon receives more rainfall.
D) South Dakota has fewer lakes and rivers.
E) South Dakota has more prevailing winds from the west.