Please explain why C is the correct over answer D in an easy to understand explanation. I read the explanation below, but am still confused. So please explain it a different way. Also, please state the rules to know to solve this question.

Question A defendant was tried for armed robbery. The state introduced evidence that a man, identified by witnesses as the defendant, entered a convenience store at 11 p.m. on March 5, threatened the clerk with a gun, and took $75 from the cash register. The defendant did not testify, but his sister did. She testified that on March 5, at the time of the robbery, the defendant was with her in a city 300 miles away. On cross-examination, the sister admitted having given a statement to the police in which she had said that the defendant was not with her on March 5, but she claimed that the earlier statement was mistaken. The court instructed the jury that in order to convict the defendant, they had to find all of the elements of the crime beyond a reasonable doubt. As to the defendant's claim of alibi, which of the following additional instructions would be proper? Alibi is a matter of defense and so must be established by the defendant; however, the burden of persuasion is by a preponderance of the evidence, not beyond a reasonable doubt. B Before you may consider the defendant's claim of alibi, you must decide whether he has produced sufficient evidence to raise the issue. C If you have a reasonable doubt as to whether the defendant was present at the convenience store at about 11 p.m. on March 5, you must find him not guilty. D If the defendant's evidence has caused you to have a reasonable doubt as to whether he was the robber, you must find him not guilty. v Extended Explanation The Due Process Clause requires that, in all criminal cases, the government prove guilt beyond a reasonable doubt. The prosecution must have the burden of proving each element of the crime charged. However, the state may impose the burden of proof upon the defendant regarding an affirmative defense, such as insanity or self-defense. As to defensive evidence that does not constitute an affirmative defense, the accused has the right under due process to introduce information to establish his innocence as to the crime charged. This does not transfer the burden of proof or persuasion to the defendant. C is correct. Because an alibi is not an affirmative defense but rather negates an essential element of the crime (the defendant's actual commission thereof), due process precludes imposing upon a defendant the burden of proving an alibi. As a result, this instruction is proper. A is incorrect. An alibi defense is an attempt to establish reasonable doubt or innocence. Because the burden does not shift to the defendant, he does not have the burden to prove his alibi by any standard, including by a preponderance of the evidence. B is incorrect. When a defendant is prosecuted for a crime, he has the right to defend himself by presenting evidence that would raise reasonable doubt in the minds of the trier of fact. There is no requirement that he produce sufficient evidence before raising a traditional defense that goes to an element of the crime, such as an alibi. D is incorrect. This instruction would be improper because it asks the jury to examine the defendant's level of evidence presented rather than to examine the prosecution's evidence. The jury should be instructed to determine whether the prosecution's evidence is sufficient or insufficient under the burden of proof, not whether the defendant produced enough evidence to establish reasonable doubt