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 of 25 carriages , each of 60 meters length , when an engine also of 60 meters length is running at a speed of 60 kmph . in what time will the train cross a bridge 1.0 km long ? 
Options: a ) 2.5 , b ) 3 , c ) 5 , d ) 7 , e ) 9

A: a
****
Q: Problem: a can do a piece of work in 18 days and b alone can do it in 10 days . b works at it for 5 days and then leaves . a alone can finish the remaining work in 
Options: a ) 5 days , b ) 6 days , c ) 7.5 days , d ) 8.5 days , e ) 9 days

A: e
****
Q: Problem: the length of the bridge , which a train 180 meters long and travelling at 45 km / hr can cross in 30 seconds , is ? 
Options: a ) 195 m , b ) 156 m , c ) 245 m , d ) 156 m , e ) 156 m

A:
a
****