explain why sunk costs should not be included in a capital budgeting analysis but opportunity costs and externalities should be included. Give an example of each - sunk cost, opportunity cost and externality (positive or negative). Use example(s) for the company Apple or refer to examples from the business news (WSJ, Bloomberg etc.) - i.e. pick an article explaining investment made by some company, pick elements of that investment explained in the article and classify these as on of the above three items.

Please add Sources and References!