Learning is a form of behavioural

Concept: Classical definitions in educational psychology (Munn, Woodworth) describe learning as a relatively permanent modification or change in behaviour that occurs as a result of experience, practice, or training.

Application: The statement "Learning is a form of behavioural ___" is completed by this very definition -- learning is best described as a process of behavioural modification, since it involves a lasting alteration in how an organism responds, brought about through experience.

Cross-check: Why the other options do not fit:

• withdrawal describes moving away from or avoiding a stimulus -- a specific response, not the defining nature of the learning process itself.

• continuation implies an existing behaviour simply persisting unchanged -- the opposite of the alteration that learning produces.

• extension implies the same behaviour merely being carried further in scope or degree, not a qualitative change in the behaviour itself.