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'.

Input: Consider Input: Problem: a person p takes 4 hrs time to complete a job and q takes 6 hrs to complete the same job if they work together how much time will they require to complete the job ? 
Options: a ) 1.2 hrs , b ) 1.8 hrs , c ) 2.4 hrs , d ) 3.0 hrs , e ) none of these

Output: c


Input: Consider Input: Problem: five bells commence tolling together and toll at intervals of 2 , 4 , 6 , 8 10 seconds respectively . in 20 minutes , how many times do they toll together ? 
Options: a ) 11 , b ) 10 , c ) 15 , d ) 16 , e ) 17

Output: a


Input: Consider Input: Problem: how long does a train 120 meters long running at the rate of 54 kmph take to cross a bridge 660 meters in length ? 
Options: a ) 33 , b ) 72 , c ) 52 , d ) 82 , e ) 62


Output: c