Answer: The structure of the sentence provided is d. compound-complex.
Explanation: A compound-complex sentence is a sentence made up of a compound sentence and a complex sentence.While a compound sentence is formed with two independent clauses, a complex sentence is formed with an independent clause and a dependent clause<u>. The sentence provided combines these two types of sentence because it is made up of two independent clauses</u> ("Cheryl made the frosting" and "Hannah made the gravy") <u>and two dependent clauses</u> ("While Paul made a cake" and "While Demitri mashed the potatoes"), which have been introduced by the subordinating conjunction "while". Moreover, the coordinating conjunction "and" has also been used.
