The core concept is understanding comma usage. In the given sentence, the comma separates the introductory adverbial phrase 'After the game' from the main clause. Option C is the correct function of the comma. Option A is incorrect as the given sentence is not two independent clause. Option B is used to list items but this is not the function in the given sentence. Option D is wrong as commas don't join subjects and verbs. The correct answer is C because it correctly identifies the usage of a comma after the introductory phrase. The comma helps clarify the sentence's structure.