Explain how the events listed in (a) through (d) would affect the following costs at Southwest Airlines:
1. Marginal cost
2. Average variable cost
3. Average fixed cost
4. Average total cost
a. Southwest signs a new contract with the Transport Workers Union that requires the airline to increase wages for its flight attendants.
b. The federal government starts to levy a $20-perpassenger carbon emissions tax on all commercial air travel.
c. Southwest decides on an across-the-board 10 percent cut in executive salaries.
d. Southwest decides to double its television advertising budget.