Fill in the blank with a suitable preposition.
The factory is _______ the river.
The prepositions ‘beside’ and ‘besides’ are often confused in spite of their difference. ‘Beside’ means on the side of something, whereas ‘besides’ means ‘other than’. Since the sentence refers to a place ‘beside’ is the apt option. Hence option C is correct, while option D is incorrect. The preposition ‘below’ is used when something is lower than something else. The factory cannot be under the river hence option A is incorrect. Whereas ‘with’ is used to refer to a tool or company, which is not apt here because the river is not accompanying the factory. Therefore option B is incorrect.