The correct answer is "Slang displays a tone that is too casual"
Slang speak is highly informal, sometimes even offensive. One should never use slang in a business setting because business deals should be kept highly informal and professional. Slang shouldn't be used under any circumstance as it may insult the people with whom we are talking by making it seem that we don't appreciate them or their business endeavors.
Marginal cost refers to the amount of money it cost a company to produce one more of a particular product while the marginal benefit refers to the benefit that is obtained as a result of producing that one extra product. Profit is maximized when the marginal cost equals the marginal benefits.
