<span><span>The message that Maureen Daly conveys in the story "Sixteen" is that in affairs of the heart it is best to use your head to temper the feelings of the heart. The main character says, "My heart still prays but my mind...</span></span>
<span>"He does not realize the demands he is making upon nature. . . . "</span>
The answer is definitely D, because it contains two independent clauses that are joined together without a comma or conjunction. (An independent clause just means a chunk of language that has both a subject and a verb and could be a complete sentence on its own.)
The correct answer is A.)