The Average Life Expectancy of Tires Produced by the Whitney $\mu$

The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles.Management believes that due to a new production process,the life expectancy of their tires has increased.In order to test the validity of their belief,the correct set of hypotheses is

A) H₀: $\mu$ < 40,000 H_a: $\mu$ $\ge$ 40,000
B) H₀: $\mu$ $\le$ 40,000 H_a: $\mu$ > 40,000
C) H₀: $\mu$ > 40,000 H_a: $\mu$ $\le$ 40,000
D) H₀: $\mu$ $\ge$ 40,000 H_a: $\mu$ < 40,000