Which sentence correctly uses a comma to separate coordinate adjectives?

Coordinate adjectives each describe the noun independently, so you can usually put “and” between them or reverse their order. In “a red, rusty gate,” both “red” and “rusty” describe the gate; “a rusty, red gate” also works. The other choices contain adjective pairs that work together as a unit, such as “bright pink” or “wood desk,” so they should not be separated with a comma.

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