The option that must be placed between coordinate adjectives is the word "and." When multiple adjectives are used to describe a noun, they are known as coordinate adjectives. In order to maintain the correct syntax and readability, the word "and" should be inserted between coordinate adjectives. This helps to clarify that each adjective is independently modifying the noun. For example, consider the phrase "She wore a beautiful, elegant dress." In this case, the word "and" is not necessary because the adjectives "beautiful" and "elegant" are not coordinate and can be used interchangeably. However, if the phrase was "She wore a beautiful and elegant dress," it would imply that the dress was both beautiful and elegant. So, to summarize, "and" is the appropriate option to place between coordinate adjectives.
