Tabes dorsalis is seen in:

Ans. is 'c' i.e., Tertiary syphilisRef:Harrison, 19th/e, p. 1132; Ananthanarayan, 9th/e, p. 370Tabes dorsalis, also known as syphilitic myelopathy, is a slow degeneration (specifically, demyelination) of the nerves primarily in the dorsal columns (posterior columns) of the spinal cord (the portion closest to the back of the body). These nerves normally help maintain a person's sense of position (proprioception), vibration and discriminative touch.Tabes dorsalis is caused by demyelination caused by advanced syphilis infection (tertiary syphilis), when the primary infection by the causative spirochete bacterium Treponema pallidum is left untreated for an extended period of time (past the point of blood infection by the organism).