Final answer:
The correct sentence that uses colons correctly is: John packed the following for his trip: an umbrella, a blanket, a sleeping bag, and a tarp.
Step-by-step explanation:
The correct sentence that uses colons correctly is: John packed the following for his trip: an umbrella, a blanket, a sleeping bag, and a tarp. The use of a colon in this sentence is appropriate because it is used to introduce a list of items that John packed for his trip. The colon serves as a punctuation mark that signals that a list is about to follow.
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