Which sentence correctly uses commas to separate coordinate adjectives?

The answer is: The long, winding corridor is illuminated with oblong skylights.

A coordinate adjective simply refers to two adjectives that modify the same word. They are adjectives that separately modify the noun that follows. In this case long and winding are both modifiers of corridor and can be referred to as coordinate adjective. The comma rule lies between the coordinate adjective and cumulative adjective.