Definition: 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: Problem: recently , i decided to walk down an escalator of a tube station . i did some quick calculation in my mind . i found that if i walk down 20 ' ' 6 steps , i require thirty seconds to reach the bottom . however , if i am able to step down thirty ' ' 4 stairs , i would only require eighteen seconds to get to the bottom . if the time is measured from the moment the top step begins to descend to the time i step off the last step at the bottom ?
Options: a ) 43 , b ) 44 , c ) 45 , d ) 40 , e ) 46
Output:
e