The first one: Death Valley, the lowest point in the United States, is located in the Mojave Desert.
**Death Valley, the lowest point in the United States, is located in the Mojave Desert. ** ;
The correct sentence is A: "Death Valley, the lowest point in the United States, is located in the Mojave Desert," as it properly capitalizes both 'Death Valley' and 'Mojave Desert.' Capitalization rules help identify proper nouns in English grammar.
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