In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: the pilot of a small aircraft with a 40 - gallon fuel tank wants to fly to cleveland , which is 480 miles away . the pilot recognizes that the current engine , which can fly only 8 miles per gallon , will not get him there . by how many miles per gallon must the aircraft ’ s fuel efficiency be improved to make the flight to cleveland possible ? 
Options: a ) 2 , b ) 4 , c ) 12 , d ) 40 , e ) 160

Ex Output:
b


Ex Input:
Problem: the speed of a car is 60 km in the first hour and 30 km in the second hour . what is the average speed of the car ? 
Options: a ) 45 kmph , b ) 65 kmph , c ) 75 kmph , d ) 85 kmph , e ) 90 kmph

Ex Output:
a


Ex Input:
Problem: a metallic sphere of radius 12 cm is melted and drawn into a wire , whose radius of cross section is 12 cm . what is the length of the wire ? 
Options: a ) 6 cm , b ) 14 cm , c ) 16 cm , d ) 23 cm , e ) 29 cm

Ex Output:

c