The speed of the wind is changing according to the function V (t) = -t/2 + 30, where t = time in minutes after 6:00 p. m. and V(t) = wind speed in miles per hour (mph). Which statement best describes the meaning of the equation V(20) – V(10) = -5?

A) In a period of 5 minutes, the wind speed increased from 10 mph to 20 mph.

B) The wind speed decreased by 5 mph between 6:10 p. m. and 6:20 p. m.

C) The wind speed increased by 5 mph between 6:10 p. m. and 6.20 p. m.

D) In a period of 5 minutes, the wind speed decreased from 20 mph to 10 mph.