The North American Plate and the Pacific Plate Are Sliding

The North American plate and the Pacific plate are sliding past one another at a rate of approximately 3 cm/year.San Francisco,which is located on the edge of the North American plate,is sliding southward toward Los Angles,which is located on the Pacific Plate.If they are currently separated by a distance of 600 km,how many years will it take for the two cities to meet?

A) 3 million years
B) 300,000 years
C) 20 million years
D) 20,000 years