Learning is generally considered as a permanent change in behavior based on:

In educational psychology, learning is defined as a relatively permanent change in behaviour (or behavioural potential) that results specifically from practice and experience — not from temporary states such as fatigue or mood, and not from maturation. The definition names two joint bases: repeated practice (rehearsal of a response) and experience (exposure gained through interacting with the environment).

The question asks what this permanent behavioural change is based on. Matching the standard definition, the change is attributed to practice and experience together, so the pairing that reproduces both of these bases is the one that answers the stem correctly.

Each other pairing swaps out one or both of these bases for a term that is not part of the standard definition:

• Practice and challenge — challenge denotes how demanding a task feels to the learner, a property of the task rather than a basis of behavioural change; it replaces experience with a task-difficulty label.

• Challenge and experience — here challenge replaces practice; task difficulty faced even repeatedly does not supply the rehearsal that repeated practice provides.

• Challenge and reinforcement — reinforcement is the operant-conditioning mechanism that strengthens one specific response after it occurs, a narrower and later concept than the two general bases in this definition, and challenge is not one of those bases either.