The military tests the endurance of potential recruits,

The military tests the endurance of potential recruits, devises various ordeals, including one that requires them to hike for 40 miles with a load of 50 pounds on their backs.

(A) recruits, devises various ordeals, including one that requires them
(B) recruits by devising various ordeals, including one that requires them
(C) recruits, devising various ordeals, including one requiring it
(D) recruits, it also devises various ordeals, including one requiring them
(E) recruits with the devising of various ordeals, including one requiring

How military tests the endurance? By devisind various ordeals. The correct structure of the sentence cannot be A because modifies the meaning :"The military tests the endurance of potential recruits, devises various ordeals" this is list of things done by the army.
Option C uses "it" and not "them"(recruits), moreover I am not sure of "devising". In D who is "it"? What does it refer to? " including one requiring" sounds awkward to me.
E uses "with the": not idiomatic.
IMO B