Task: Question Answering
Input (English): Problem: if greg buys 3 shirts , 6 trousers and 4 ties , the total cost is $ 80 . if greg buys 7 shirts , 2 trousers and 4 ties , the total cost is $ 80 . how much will it cost him to buy 5 trousers , 4 shirts and 4 ties ? 
Options: a ) $ 60 , b ) $ 64 , c ) $ 80 , d ) $ 96 , e ) can not be determined
Output (English): c