Final answer:
The identity of who killed Roger in Mr. Fields's botany class at the State Gardens Museum cannot be determined without specific context or additional information from the source material. It is important to review the text for clues or evidence.
Thus, the corret option is D.
Step-by-step explanation:
The question seems to be referencing a specific scenario, likely from a piece of literature, where a character named Roger from Mr. Fields's botany class was killed at the State Gardens Museum. Without additional context, such as the title of the book or story this scenario is from, it is impossible to definitively answer who killed Roger. The options provided are A. Kirk, B. Melissa, C. Someone else, and D. The murderer is unknown. If this is a question from a book or story you have been reading in class, the answer should be found within the text. Please review the relevant sections to find clues or explicit evidence that points to the perpetrator. If this information is not provided within the text, then the likely answer might be D. The murderer is unknown.
Therefore, the corret option is D. The murderer is unknown.