Task: Question Answering
Input (English): Problem: for what values of k will the pair of equations 3 x + 4 y = 12 and ( kx + 12 y ) / 2 = 15 does not have a unique solution ? 
Options: a ) 12 , b ) 9 , c ) 3 , d ) 7.5 , e ) 2.5
Output (English): b