Markets are generally efficient (maximize producer surnlu plus consumer surplus), so economists argue the role of government in markets is limited to objectives other than efficiency (such as reducing inequality) and addressing market failures (or market imperfections). Some market imperfections can also be mitigated by firms. Which of the following is not an example of how governments or firms mitigate market failures (or market imperfections)?

A. governments make vaccines available to consumers at below cost prices.

B. regulatory agencies require manufacturers to install equipment that reduces smokestack emissions.

C. firms invest in reputations for delivering safe and reliable products.

D. governments tax personal income in order to pay for foreign aid.

E. workers pay for training programs to demonstrate to potential employers that they are more productive