Task: Question Answering
Input (English): Problem: when toys are grouped into 12 and 18 , always 3 toys remain ungrouped . what is the minimum number of toys to be added so that when they are grouped into 7 , no toys will remain ungrouped ? 
Options: a ) 0 , b ) 1 , c ) 2 , d ) 3 , e ) 4
Output (English): d