Sentence Correction

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

OA is B
pls, whats wrong with option A. I want an Expert contribution pls. Thanks