Sam is a customer service executive at an apparel store. He went beyond his primary job of assisting customers to suggest outfits that would suit the customers. This gesture was well appreciated by the customers. The company's manager immediately rewarded Sam with a bonus to motivate Sam to repeat the behavior. Which of the following theories of motivation did the manager adopt in this case?
1) Maslow's Hierarchy of Needs
2) Herzberg's Two-Factor Theory
3) Expectancy Theory
4) Equity Theory