There is a vending machine at work that gives extra candy bars when you select either the ""A"" or ""B"" choices. You continue to frequent this machine regularly. Your action best illustrates:

The answer is operant conditioning.

Explanation:

Operant conditioning is an approach to learning psychology which intends to understand to movation behind individual behaviour. Is states that people are more likely to repeat an action when it is reinforced.

In the example, you continue visiting the vending machine because your behaviour is positively reinforced, whch means you get a reward after a certain action is completed.  

answer; i believe the correct answer is (4) flip a coin as each participant arrives,heads indicates assignment to the first group: tails indicates assignment to the second group;

i think the answer is true : ))