Task: Question Answering
Input (English): Problem: in a certain archery competition , points were awarded as follows : the first place winner receives 11 points , the second place winner receives 7 points , the third place winner receives 5 points and the fourth place winner receives 2 points . no other points are awarded . john participated several times in the competition and finished first , second , third , or fourth each time . the product of all the points he received was 53900 . how many times did he participate in the competition ? 
Options: a ) 7 , b ) 8 , c ) 9 , d ) 10 , e ) 11
Output (English): a