Final answer:
The Radial Side of the Index Finger (LU), option c, is involved with separating the impure from the pure in the context of traditional Chinese medicine's Lung meridian.
Step-by-step explanation:
The meridian involved with separating the impure from the pure, according to traditional Chinese medicine, is the Radial Side of the Index Finger (LU), represented here by option c.
This meridian is associated with the Lung meridian of acupuncture, which is said to be responsible for respiratory functions and also plays a role in the body's immune response.
The radial notch of the ulna is a small, smooth area on the lateral side of the proximal ulna that articulates with the head of the radius as part of the proximal radioulnar joint.
The radius bone is located on the lateral side of the forearm, and it does not articulate with any of the carpal bones.
This anatomical information, while detailed, is more relevant to the physical structure of these bones rather than their association with the concepts of impurity and purity in Chinese medicine.