Explanation:
The correct option is 'a'. The axillary nerve is the most frequently injured nerve during an anterior shoulder dislocation due to its anatomic course winding around the surgical neck of the humerus. Injury results in motor weakness of the deltoid and teres minor (impairing shoulder abduction) and sensory loss over the lateral deltoid area, commonly referred to as the 'regimental badge' patch.

Reference: Robinson CM, Shur N, Sharpe T, Ray A, Olabi B. Structural and functional impairment associated with nerve injuries following anterior shoulder dislocations. J Bone Joint Surg Am. 2012;94(5):445-452.