Answer:
a real snoop
( if it isn't this, then the answer is "a questioning character" )
Explanation:
Since negative connotations are basically words that give people a bad feeling when they hear it, we can apply this knowledge to these choices.
A questioning character: This could mean someone who seems suspicious or someone who just comes off as weird to people.
An inquisitive character: the word "inquisitive" is basically another word for "curious."
A real snoop: "snoop" is someone, or when someone, is prying and going through your stuff. Usually, when someone is said to be a "snoop," it's usually in an invasive sense.
A curious student: This doesn't signify that this person is doing anything wrong or negative.