B

Losing vision makes the gait collapse (positive Romberg) and the patient compensates by stamping to enhance proprioceptive cues—classic “sensory ataxia.” Proprioception from the limbs ascends in the dorsal (posterior) columns; lesions here, as in tabes dorsalis or sensory neuropathies, produce exactly this stamping-gait pattern, whereas cerebellar or vestibular tract lesions cause imbalance even with eyes open [Housman, 2014, PMID 22711686; Missaoui, 2009, PMID 19853794].