What is the way of modifying behaviour through Operant Conditioning?

English: Operant conditioning modifies behaviour mainly through shaping — refining existing behaviours by reinforcing successive approximations toward a target response. Identify the final target behaviour.

Reinforce small, successive approximations of the target behaviour.

Gradually require closer approximations before giving reinforcement until the full behaviour occurs.

Choose appropriate types and schedules of reinforcement to strengthen and maintain the behaviour.

Note: Simple repetition or drill is not the defining mechanism in operant conditioning; repetition may increase practice but shaping by reinforcement explains how new or complex behaviours are acquired. Of the provided choices, the option that describes "refinement of existing behaviours" best matches operant-conditioning shaping and should be considered the correct conceptual answer.