Which of the following sentences correctly uses a compound sentence structure?

Choice C correctly uses a compound sentence structure with the conjunction 'but' to join two independent clauses. In a compound sentence, two independent clauses are joined to create a longer sentence that provides more information or shows a relationship between the ideas presented in each clause. In this case, the independent clauses are 'He liked to cook at home' and 'she preferred to eat at restaurants,' connected by the coordinating conjunction 'but.' This structure makes the sentence more complex and informative.