Task: Question Answering
Input (English): Problem: if ( a + b ) = 16 , ( b + c ) = 9 and ( c + d ) = 3 , what is the value of ( a + d ) ? 
Options: a ) 10 . , b ) 8 . , c ) 7 . , d ) 2 . , e ) - 2 .
Output (English): a