17. If the jury believes the defendant's testimony and finds that her mistaken belief that the gun was a prop was reasonable, they should find her

D is correct. The defendant is using a mistake of fact defense. She incorrectly believed that the gun was a prop, not a real gun, and that it would fire blanks. Mistake of fact may be a defense only if it negates the state of mind required for the crime. Here, a mistake of fact would negate the mental states needed for both murder and manslaughter. However, for malice and general intent crimes, there is an extra requirement that the mistake of fact must be reasonable (i.e., the type of mistake that a reasonable person would have made under the circumstances). In this case, murder and manslaughter are general intent or malice crimes. Therefore, if the jury believes that the mistake of fact made by the defendant is reasonable, it is a valid defense to both crimes.

A is incorrect. If the jury finds that the defendant's mistake of fact defense is reasonable, it would negate the state of mind requirement for the general intent crime of murder.

B is incorrect. If the jury finds that the defendant's mistake of fact defense is reasonable, it would negate the state of mind requirement for manslaughter, which is a general intent crime.

C is incorrect. As stated above, if the jury were to find that the defendant's mistake of fact was reasonable, it would negate the intent requirement for both murder and manslaughter, which are general intent crimes.