Task: Question Answering
Input (English): Problem: six bells commence tolling together and toll at intervals of 2 , 4 , 6 , 8 10 and 12 seconds respectively . in 30 minutes , how many times do they toll together ? 
Options: a ) 4 , b ) 10 , c ) 15 , d ) 16 , e ) none
Output (English): d