What do commas separate in a list?

Commas are used to separate items in a series, which is essential for clarity and readability. In a sentence that lists multiple elements, placing commas between each item helps the reader distinguish them as separate entities. For example, in the sentence "I bought apples, oranges, bananas, and grapes," the commas clearly indicate that these fruits are distinct items in the list.

Using commas in this way not only helps organize information, but it also prevents confusion that could arise if items were presented together without any separation. This makes option B the correct choice, as it directly addresses the function of commas in a list context. The other options do not pertain to the purpose of commas in separating elements within a list.