Final answer:
The preposition in the sentence is 'around' and the object of the preposition is 'boat', making the correct answer C. preposition: around; object of the preposition: boat.
Step-by-step explanation:
The sentence in question is, "A small friendly dolphin swam around our boat." In this sentence, the preposition is the word that shows the relationship of the noun to another element in the sentence, and the object of the preposition is the noun or pronoun that follows the preposition and gives it meaning. The preposition in this sentence is 'around', which shows the relationship between the action of swimming and the boat. The object of the preposition is 'boat', as it is what the dolphin is swimming around. Therefore, the correct answer to the question is C. preposition: around; object of the preposition: boat.