Task: Question Answering
Input (English): Problem: the average age of 15 students of a class is 15 years . out of these , the average age of 6 students is 14 years and that of the other 9 students is 16 years , the age of the 15 th student is 
Options: a ) 11 , b ) 12 , c ) 13 , d ) 14 , e ) 15
Output (English): c