The sentence that corrects the dangling modifier is:
"While I was eating a slice of watermelon, pink juice dribbled down my chin."
This sentence avoids the ambiguity since it is clear that it is not the "pink juice" that is "eating a slice of watermelon" but "I".
The rest of the options fall into the category of dangling modifiers as they do not include the target that is being modified.
When the target that is modified is not clear, it generates confusion in the reader.
