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'.
--------
Question: Problem: a and b can do a piece of work in 8 days . with the help of c they finish the work in 4 days . c alone can do that piece of work in ? 
Options: a ) 40 days , b ) 20 days , c ) 8 days , d ) 60 days , e ) 40 days

Answer: c


Question: Problem: a train is 300 meter long is running at a speed of 35 km / hour . in what time will it pass a bridge of 115 meter length ? 
Options: a ) 29 , b ) 23 , c ) 47.119 , d ) 44.586 , e ) 42.686

Answer: e


Question: Problem: alice and bob drive at constant speeds toward each other on a highway . alice drives at a constant speed of 30 km per hour . at a certain time they pass by each other , and then keep driving away from each other , maintaining their constant speeds . if alice is 100 km away from bob at 7 am , and also 100 km away from bob at 11 am , then how fast is bob driving ( in kilometers per hour ) ? 
Options: a ) 20 , b ) 24 , c ) 28 , d ) 32 , e ) 36

Answer:
a