Answer:
Cryptic
Explanation:
Cryptic means "having a meaning that is mysterious or obscure," so this would be the right answer
Why the others aren't correct:
Boisterous- Noisy, energetic, cheerful, rowdy [This doesn't fit the sentence]
Petulant- Childishly sulky [pouty] or bad tempered [This doesn't fit the sentence]
Jovial- Cheerful and friendly [This doesn't fit the answer]
Thus, the answer is cryptic.
I hope this helps!