If the Area Shown in This Figure Is 240 Kilometers

Multiple Choice

If the area shown in this figure is 240 kilometers wide, and the oldest crest is 4 million years old, what was the approximate rate of seafloor spreading across this ridge?

A) 0.24 kilometers per million years
B) 2.4 kilometers per million years
C) 60 kilometers per million years
D) 240 kilometers per million years
E) 960 kilometers per million years