Task: Question Answering
Input (English): Problem: lamp a flashes every 6 seconds , lamp b flashes every 8 seconds , lamp c flashes every 10 seconds . at a certain instant of time all 3 lamps flash simultaneously . during the period of 6 minutes after that how many times will exactly two lamps flash ? ( please include any flash of exactly two lights which occurs at the 6 minute mark . ) 
Options: a ) 24 , b ) 25 , c ) 26 , d ) 27 , e ) 28
Output (English): d