A person walks at a speed of 4 km/hr and runs at a speed of 8 km/hr. How many hours will the person require to cover a distance of 12 km, if the person completes half of the distance by walking and the other half by running?	Choose the correct choice from the following:
A) 1.25 B) 1.75 C) 2.25 D) 2.75 E) 3.25

Rationale: "time = 6 / 4 + 6 / 8 = 18 / 8 = 2.25 hours the answer is c ."
Answer: C