Task: Question Answering
Input (English): Problem: 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 4 km , if the person completes half of the distance by walking and the other half by running ? 
Options: a ) 0.25 , b ) 0.5 , c ) 0.75 , d ) 1 , e ) 1.25
Output (English): c