Correct the sentence: where is the necklace from your sister and the earrings from your cousin?
Where is the necklace from your sister and the earrings from your cousin?
Where is the necklace from your sister, and where are the earrings from your cousin?
To correct the sentence, you can make it more clear and grammatically correct by restructuring it. Here's a corrected version:
"Where is the necklace from? Is it from your sister? And where are the earrings from? Are they from your cousin?"