[Solved] Combinations of a long-acting nitrate and a beta blocker are especially effective in treating angina because: A) Nitrates increase MOS and beta blockers increase MOD. B) Their additive effects permit lower doses of both drugs and their adverse reactions cancel each other out. C) They address the pathology of patients with exertional angina who have fixed atherosclerotic coronary heart disease. D) All of the above Perfectly Elastic: Describes a situation where the quantity demanded or supplied changes by an infinite amount in response to any change in price; most common in theoretical models. Total Costs: The total amount of expenses a business has for producing goods or services, encompassing both constant and fluctuating costs. Elasticity of Demand: An indicator quantifying the impact of price movements on demand for a good. Elasticity Coefficient: A measure of how much the quantity demanded or supplied of a good responds to a change in price, income, or another economic factor.