The preposition "at" is the most appropriate to be used in this sentence, as shown in option C.
Prepositions are very important for a sentence or text to be meaningful. There are many different prepositions and knowing how to use them correctly is essential for a good writer.
The preposition "at," for example, should always be used to indicate a specific place, with the heart.
More information about prepositions is in the link:
https://brainly.com/question/17476214