Final answer:
The correct code for the admission of a patient with pain control secondary to metastatic carcinoma of the spinal cord is C79.9.
Step-by-step explanation:
The patient is admitted for pain control secondary to metastatic carcinoma of the spinal cord. The correct answer for the code representing this condition is option a) C79.9, which stands for secondary malignant neoplasm of unspecified site. Options b) G95.20, c) M48.50, and d) G89.4, represent other conditions related to the spinal cord and pain but do not accurately describe metastatic carcinoma of the spinal cord, which is the primary concern in this case.