<u>D. The economy or the weather can make a small town fall apart.</u>
Explanation:
A compound subject is a subject consisting of two or more nouns. When a sentence has a compound subject, the nouns are often joined by a comma or by coordinating conjunction like <em>or, nor, and </em>or<em> neither</em>. In sentence D, "The economy or the weather" is a compound subject because both nouns act as subjects (They perfom the main action), and they are joined by "or."
