Task: Question Answering
Input (English): Problem: in an examination , a student scores 5 marks for every correct answer and loses 2 marks for every wrong answer . if he attempts all 100 questions and secures 290 marks , the number of questions he attempts correctly , is : 
Options: a ) 60 , b ) 80 , c ) 70 , d ) 45 , e ) 50
Output (English): c