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'.

Problem: how many seconds will a 1200 m long train take to cross a man walking with a speed of 3 km / hr in the direction of the moving train if the speed of the train is 63 km / hr ?
Options: a ) 26 sec , b ) 65 sec , c ) 55 sec , d ) 19 sec , e ) 72 sec
e

Problem: how long does a train 165 meters long running at the rate of 54 kmph take to cross a bridge 660 meters in length ?
Options: a ) 55 sec , b ) 40 sec , c ) 45 sec , d ) 30 sec , e ) 35 sec
a

Problem: the citizens of planet nigiet are 5 fingered and have thus developed their decimal system in base 8 . a certain street in nigiet contains 1000 ( in base 5 ) buildings numbered 1 to 1000 . how many 3 s are used in numbering these buildings ? express result in terms of base 10 .
Options: ['a ) 54', 'b ) 64', 'c ) 75', 'd ) 85', 'e ) 100']
c