Correct option is (c) reverted gear train
To explain I would say: When there is only one gear on each shaft, it is known as simple gear train.
When there are more than one gear on a shaft, it is called a compound train of gear.
When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear train.