Final answer:
Receiving a high rating on customer service is an example of an extrinsic reward.
Step-by-step explanation:
An extrinsic reward is a reward that comes from outside of oneself and is typically tangible or visible. Out of the options given,
receiving a high rating on customer service would be an example of an extrinsic reward. It is an external recognition of good performance. The other options, such as appreciation mail from a customer, promotions based on performance, and verbal appreciation from the CEO, are all forms of intrinsic rewards as they provide internal satisfaction and motivation.