The correct answer would be "D. She washed the shells and dried themm in the sun.". First, we should know what a <em>compound predicate</em> is. A compound predicate is when a subject has 2 or more verbs. In your sentence, you have two verbs, which are <em>washed</em> and <em>dried.</em>
The correct answer among all the other choices is C. simple and rhythmic. This is the kind of sound the poem's rhyme and meter create in "The Rainy Day." Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.