What is 0.25 kilometers expresses in centimeters

The answer is:

A.

Each kilometer has 1000 meters and each meter has 100 centimeters

So there is 100,000 centimeters in a km because 100 x 1000 is 100,000

0.25 km has 25,000 centimeters because 100,000 x 0.25 is 25,000

0.25km = 250m = 25000cm