Final answer:
Option b) correctly uses commas to separate a list of adjectives describing a noun. The adjectives 'fresh' and 'interesting' both modify 'approach' and are properly separated by a comma.
Step-by-step explanation:
The correct usage of commas can be seen in option b) Celeste spent three hours working on a fresh, interesting approach to the client's problem. Here, commas are used appropriately between a list of adjectives that describe an approach. It adheres to the rule: when you have multiple adjectives before a noun, you can separate them with commas. For example, in the phrase 'a fresh, interesting approach,' the adjectives 'fresh' and 'interesting' both modify 'approach' and are separated by a comma. This use of the comma helps the reader understand that these are separate qualities of the approach, not a combined quality.
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