Task: Question Answering
Input (English): Problem: of the 200 stamps in a collection , 90 are foreign and 70 are more than 10 years old . if 20 stamps are both foreign and more than 10 years old , how many stamps are neither foreign nor more than 10 years old ? 
Options: a ) 60 , b ) 80 , c ) 100 , d ) 130 , e ) 150
Output (English): a