Which of the following is true regarding commas?

Using commas to separate items in a list is a fundamental rule of English punctuation. This practice helps organize information clearly and allows readers to easily identify individual items. For example, in the sentence, "I bought apples, oranges, bananas, and grapes," commas effectively delineate each item in the list, thereby enhancing readability.

The other statements are inaccurate. Commas can indeed be used before conjunctions in compound sentences, such as in "I want to go to the park, but it's raining." They cannot replace periods at the end of sentences, as a period indicates the end of a complete thought, while a comma serves to connect related ideas or items within a sentence. Also, commas are typically not used to join independent clauses without conjunctions; this would require a semicolon instead. Therefore, the rule about commas separating items in a list stands out as the accurate statement among the options.