Correct Option: D

Skandgupta was the Gupta ruler who defeated the Hunas. Soon after his accession, Skandagupta had to face the Hunas who had already proved themselves to be terror to both Europe and Asia. About the middle of the fifth century AD, one branch of the Hunas known as White Hunas occupied the Oxus valley and threatened both Persia and India. They conquered Gandhara and threatened the very existence of the Gupta empire. Skandgupta inflicted such a terrible defeat upon the Hunas that they dared not disturb the empire for nearly half a century.