Final answer:
The underlined portion 'Ron finished writing his essay' contains both a subject and a verb, and can stand alone as a complete thought, which makes it an independent clause (Option A).
Step-by-step explanation:
To classify the underlined portion of the sentence 'Ron finished writing his essay,' we need to determine if it has both a subject and a verb and if it can stand alone as a complete thought. The underlined portion, which we can assume to be 'finished writing his essay' given the context of the question, contains a subject ('Ron') and a predicate ('finished writing his essay'). Since it has a subject and verb and can stand alone as a sentence, it is an independent clause. Therefore, the underlined portion would be classified as option A, an independent clause.
Independent clauses have the ability to stand alone as a complete sentence, which is why 'Ron finished writing his essay' can be considered both an independent clause and a simple sentence. However, as per the options provided, the most accurate classification is 'Independent clause.'