Task: Question Answering
Input (English): Problem: if the average ( arithmetic mean ) of a and b is 45 and the average of b and c is 80 , what is the value of c â ˆ ’ a ? 
Options: a ) 25 , b ) 70 , c ) 90 , d ) 140 , e ) it can not be determined from the information given
Output (English): b