Answer:
The answer is b. shaping.
Explanation:
Shaping refers to the process of reaching a desired behaviour by reinforcing other similar behaviour. This is known as "successive approximations". For example, if a researcher is trying to teach a rat to pull a level, he might start by reinforcing the rat for standing near the lever. The reward then stops and another similar behaviour is reinforced, such as touching the lever. Eventually, the desired behaviour should take place.