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 Q]: Problem: a 600 meter long train crosses a signal post in 15 seconds . how long will it take to cross a 3 kilometer long bridge , at the same speed ? 
Options: a ) 4 min , b ) 2 min , c ) 8 min , d ) 9 min , e ) 1.5 min
[EX A]: e

[EX Q]: Problem: the radius of a circular wheel is 1.75 m , how many revolutions will it make in traveling 1 km ? 
Options: ['a ) 1000', 'b ) 2788', 'c ) 2677', 'd ) 2899', 'e ) 2771']
[EX A]: a

[EX Q]: Problem: one pump drains one - half of a pond in 1 hours , and then a second pump starts draining the pond . the two pumps working together finish emptying the pond in one - half hour . how long would it take the second pump to drain the pond if it had to do the job alone ? 
Options: a ) 1 hour , b ) 1.2 hour , c ) 3 hours , d ) 5 hours , e ) 6 hours
[EX A]:
c