Detailed Instructions: In this task, you need to provide the correct option for a given problem from the provided options.
Q: Problem: there are 100 lights which are functional and each is controlled by a separate on / off switch . two children a and b start playing with the switches . a starts by pressing every third switch till he reaches the end . b , thereafter , presses every fifth switch till he too reaches the end . if all switches were in off position at the beggining , how many lights are switched on by the end of this operation ? 
Options: a ) 13 , b ) 41 , c ) 47 , d ) 48 , e ) 53
A:
b