Explanation:
The correct option is 'd'. Central cord syndrome is the most common incomplete spinal cord injury, typically occurring in older patients with pre-existing cervical spondylosis who sustain a hyperextension injury. The central location of the injury disproportionately affects the medially located cervical motor tracts (supplying the upper extremities) more than the laterally located lumbar and sacral tracts (supplying the lower extremities).

Reference: Schneider RC, Cherry G, Pantek H. The syndrome of acute central cervical spinal cord injury; with special reference to the mechanisms involved in hyperextension injuries of cervical spine. J Neurol Neurosurg Psychiatry. 1954;17(4):253-260.