Unlike its competitors, GoGo had to spend substantial amounts to build a network of ground-based cellular towers. It has to abandon those towers as it switches to a satellite-based network. Is the cost of those towers a disadvantage to GoGo as it competes with the new firms entering the industry? Briefly explain. In economic decison-making, the cost of the original towers is A. a marginal cost that requires higher prices. B. an opportunity cost that can be ignored. C. a fixed cost that reduces profits. D. a sunk cost that is irrelevant