Mike Wants to Know How Many Licks It Takes to Get

Mike wants to know how many licks it takes to get to the center of his all-day sucker.He tells his friends that "one full gyration of the tongue around the outer surface of the lollipop" is what constitutes a "lick." In an informal way,Mike is offering a(n) :

A) measurement instrument to answer his question.
B) way to eliminate the reactivity sometimes associated with observation.
C) operational definition for the behavior he wants to measure.
D) naturalistic observation.