Answer to Question 1
There are several possible explanations. Firms might voluntarily install pollution abatement equipment if they believe consumers will eventually learn about the firm's polluting behavior and stop buying its products. In some cases, the payoffs may be more complex than just monetary payoffs. For example, people may care about the net benefits that someone else receives. If this is the case, then behavior may reflect social preferences, meaning that the individual's benefits are defined not only by his own payoffs, but also by the payoffs of others. In other examples the implications of a repeated relationship are very different from a game that is played just once.
Answer to Question 2
B