Question

Which option must be placed between coordinate adjectives?

Answer 1

When you have coordinate adjectives, which are adjectives that equally describe a noun and can be separated by a conjunction ("and"), you typically place a comma between them. For example, in the phrase "The tall, dark man," the adjectives "tall" and "dark" are coordinate adjectives, and the comma separates them.

If you're looking for a specific option to place between coordinate adjectives, the answer is a comma (or "and" in some cases if not using a comma).