Find out the correct statement. One statement alone is right.

a) Samudragupta annexed all his conquered territories of South India.
b) The Dakshinapatha expedition of Samudragupta was mentioned by Fahien.
c) Samudragupta defeated the South Indian kings but gave them back their kingdoms.
d) The North Indian conquests of Samudragupta did not result in the expansion of the Gupta empire.