Task: Question Answering
Input (English): Problem: a and b walk around a circular track . they start at 9 a . m . from the same point in the opposite directions . a and b walk at a speed of 2 rounds per hour and 3 rounds per hour respectively . how many times shall they cross each other before 11 : 00 a . m . ? 
Options: a ) 8 , b ) 7 , c ) 6 , d ) 15 , e ) 3
Output (English): d