Task: Question Answering
Input (English): Problem: in a class , 6 students can speak tamil , 15 can speak gujarati and 6 can speak h . if two students can speak two languages and one student can speak all the 3 languages , then how many students are there in the class ? 
Options: a ) 20 , b ) 21 , c ) 22 , d ) 23 , e ) 24
Output (English): d