Part II: The Tufts Center for the Study of Drug Development estimates the research and development (R&D) cost to bring a drug to the market is over $2.8 billion and the cost of manufacturing a chemical compound tends to be minimal. Does this study explain why a new drug is more expensive than drugs that have been on the market for a long time? To explain these costs in our general cost function format, which one is a fixed cost and which one is a variable cost