You need a slight stop there to collect your thoughts, especially when the next word is achromatopsia. That makes D wrong.
If you use B, " A medical condition that limits her vision" is not a sentence. So B shouldn't be the answer. Fragments are used by very good writers usually in fiction, and this statement is not part of something that is fictional.
A semicolon separates two equal clauses. You can think of it as meaning "and" or even "but" sometimes. You have the same problem with C as you do with B. So C is not correct.
That leaves us with A. That should be your answer.You need a pause of some kind and that pause is proved by the comma. The sentence is not a run on sentence just one in need of a pause in the middle.
The correct answer is:
<span>King Acrisius and King Polydectes try to kill Perseus</span>
vernacular (by Native American tribes)
romantic (Othello, Hamlet etc)
The opinion about the Russian society that Leo Tolstoy expresses in this excerpt from The Death of Ivan Ilyich is the following one:
<span>D. Peasants more readily accepted unpleasant facts of life, while the middle class tried to deny them.
We can see that Ivan's servant is with him all along during his sickness, helping him and understanding what is going on, whereas people who belong to the middle or upper class regard his condition with disgust. </span>
