Which sentence correctly uses a comma to separate coordinate adjectives?

Coordinate adjectives each describe the noun independently, so you can usually switch their order or place “and” between them. In “a red, rusty gate,” both “red” and “rusty” describe the gate; “a rusty, red gate” and “a red and rusty gate” both work. The other choices pair an adjective with a word that specifies the material or type, or a color phrase, so those words are not coordinate adjectives.

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