Final answer:
Without additional context from the text, it is impossible to accurately determine whether Charlie, Johnson, Black, or White is the correct name to fill in the blank in the given sentence.
Step-by-step explanation:
The sentence provided is incomplete without choosing a proper noun to fill in the blank. Each option given, Charlie, Johnson, Black, and White, is a proper noun that could potentially fit in the blank, but without additional context, such as a reference in a book or a previous part of the text, there is no way to determine which name is the correct answer to this question. When addressing questions like these in English, it's crucial to look for contextual clues that may indicate which proper noun is appropriate. The completeness of the sentence structure suggests a need for a singular subject to take the action of leaping into the poisoned waters. Therefore, any of the provided names could grammatically complete the sentence, but the context is necessary to choose the right one.