Task: Question Answering
Input (English): Problem: in the number 11,0 ab , a and b represent the tens and units digits , respectively . if 11,0 ab is divisible by 50 , what is the greatest possible value of b × a ? 
Options: a ) 0 , b ) 5 , c ) 20 , d ) 15 , e ) 25
Output (English): c