A 17-year-old boy presents to the emergency department after road side accident due to the skid of his bike with symptoms of drooping of the right shoulder with difficulty in lifting the arm against gravity, adduction and external rotation is ok, plain radiographs reveal the fracture of clavicle lateral one-third. Which nerve is most likely injured In this case? Any other investigation to suggest? A.

Brachial plexus B. Median nerve C. Radial nerve D. Axillary nerve