Task: Question Answering
Input (English): Problem: in a class of 210 students , 70 did not opt for math . 55 did not opt for science and 42 did not opt for either . how many students of the class opted for both math and science ? 
Options: a ) 123 , b ) 125 , c ) 127 , d ) 137 , e ) 148
Output (English): c