Correct Answer: mischivious

Solution : The third option is the correct answer.

The incorrectly spelled word is mischivious.

The correct spelling is mischievous, which means playfully causing annoyance, harm, or trouble; naughty.

The meanings of the other options are as follows:

• Mysterious means difficult or impossible to understand, explain, or identify.
• Ridiculous means deserving or inviting mockery; absurd.
• Humorous means causing laughter or amusement; funny.

Therefore, the correct answer is mischievous.