Depression anterior to the anterior deltoid and superior to the lower end of the medial head of the deltoid, 7 cun above LI 11 on the radial side of the humerus. The point is located on the path of the posterior cutaneous nerve of the arm. Identify the acupuncture point:
a) LI 11
b) Anterior deltoid
c) Radial side of the humerus
d) Posterior cutaneous nerve of the arm