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'.

Example Input: Problem: how long does a train 165 meters long running at the rate of 54 kmph take to cross a bridge 660 meters in length ? 
Options: a ) 55 sec , b ) 40 sec , c ) 45 sec , d ) 30 sec , e ) 35 sec
Example Output: a

Example Input: Problem: annika hikes at a constant rate of 12 minutes per kilometer . she has hiked 2.75 kilometers east from the start of a hiking trail when she realizes that she has to be back at the start of the trail in 40 minutes . if annika continues east , then turns around and retraces her path to reach the start of the trail in exactly 40 minutes , for how many kilometers total did she hike east ? 
Options: a ) 3.625 , b ) 3.5 , c ) 3 , d ) 3.04 , e ) 4
Example Output: d

Example Input: Problem: the consumption of diesel per hour of a bus varies directly as square of its speed . when the bus is travelling at 60 kmph its consumption is 1 litre per hour . if each litre costs $ 60 and other expenses per hous is $ 60 , then what would be the minimum expenditure required to cover a distance of 600 km ? 
Options: a ) 120 , b ) 1250 , c ) 1200 , d ) 1100 , e ) 1150
Example Output:
c