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: convert 0.35 in to a vulgar fraction ? 
Options: a ) 18 / 50 , b ) 16 / 50 , c ) 7 / 20 , d ) 19 / 50 , e ) none
[EX A]: c

[EX Q]: Problem: 8 persons can build a wall 140 m long in 42 days . in how many days can 30 persons complete a similar wall 100 m long ? 
Options: a ) 12 , b ) 10 , c ) 8 , d ) 6 , e ) 5
[EX A]: c

[EX Q]: Problem: a train running at the speed of 108 km / hr crosses a pole in 7 seconds . find the length of the train . 
Options: a ) 150 meter , b ) 145 meter , c ) 140 meter , d ) 135 meter , e ) 210 meter
[EX A]:
e