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'.

[Q]: Problem: a train running at the speed of 54 km / hr crosses a pole in 7 seconds . find the length of the train . 
Options: a ) 150 meter , b ) 105 meter , c ) 140 meter , d ) 135 meter , e ) none of these
[A]: b


[Q]: Problem: a man can row upstream at 5 kmph and downstream at 25 kmph , and then find the speed of the man in still water ? 
Options: a ) 15 , b ) 77 , c ) 30 , d ) 88 , e ) 34
[A]: a


[Q]: Problem: working together , a and b can do a job in 6 days . b and c can do the same job in 10 days , while c and a can do it in 7.5 days . how long will it take if all a , b and c work together to complete the job ? 
Options: a ) 4 days , b ) 5 days , c ) 8 days , d ) 9 days , e ) 10 days
[A]:
b