The correct answer is Option C.
The phrase 'a roller coaster ride' is generally used to convey a ride that causes amusement and thrill.
We are to complete the given sentence with the word that correctly describes the ride in a bus over the pot-holed road. Such a journey over the pot-holed road is one of ups and downs and reminds of a roller coaster ride which also is full of ups and downs, jerks and bumpy. Hence Option C is the correct answer.
The remaining options are incorrect because:
Options A,B and D i.e. train, boat and bicycle rides do not cause excitement and amusement. It is not jerky and full of ups and downs and therefore bears no similarity with a roller coaster ride.
Thus Option C is the correct answer.