A student is running a 3-kilometer race. He runs 1 kilometer every 2 minutes. Select the function that describes his distance from the finish line after x minutes

A. f(x) = − 1/3x + 2
B. f(x) = − 1/2x + 3
C. f(x) = 1/2x + 3
D. f(x) = 1/3x + 2