The BEST definition for mouthing behavior would be any instance of Luke.

The BEST definition for mouthing behavior would be any instance of Luke.
A . placing his mouth on any object for at least 5 seconds.
B . placing his open mouth on a non-nutritive object or placing a non-nutritive object in his mouth.
C . making contact with his mouth to any non-nutritive object.
D . mouthing a non-nutritive item for 3 or more consecutive instances within a 30 second interval.

Answer: B