A client is admitted with leukopenia and is scheduled for a bone marrow aspiration. The practical nurse (PN) assists in positioning the client for specimen collection by exposing which site?

A. Right clavicle and upper thorax: Not a standard site for bone marrow aspiration. B. Left lower abdomen: Incorrect; bone marrow aspiration is not performed in the abdomen. C. Posterior iliac spine: This is the preferred site in adults due to accessibility and safety. D. Lower lumbar vertebrae: Rarely used; risk of injury to spinal structures.