How to find the average value of a function on an interval

Ais a mountain created from eruptions of lava, ash, rocks, and hot gases.

The gulf stream is a warm water current that flows away from the equator to northern europe. witch of these does it cause. a. crashes of warm and cool water in the ocean b.colder climates near the equator c.large waves on the cost of europe d.warm climates in northern europe

Ab c or d ? i’m not sure what the answer is