In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[EX Q]: Problem: what is the greatest value of positive integer x such that 2 ^ x is a factor of 100 ^ 50 ? 
Options: a ) 70 , b ) 80 , c ) 90 , d ) 100 , e ) 120
[EX A]: d

[EX Q]: Problem: if z is not equal to zero , and z = 6 zs − 9 s 2 − − − − − − − − √ z = 6 zs − 9 s 2 , then z equals : 
Options: a ) s , b ) 3 s , c ) 4 s , d ) - 3 s , e ) - 4 s
[EX A]: b

[EX Q]: 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
[EX A]:
a