What restrictions must the restaurant impose on the customer in order to make a profit?

1- Why is the price elasticity of demand for Coca-Cola greater than price elasticity of demand for soft drinks generally?2- Some restaurants offer “all you can eat” meals. How is this practice related of diminishing marginal utility? What restrictions must the restaurant impose on the customer in order to make a profit?3- Explain why the marginal cost of production must increased if the marginal product of the marginal resource is decreasing.4- Define productivity efficiency and allocative efficiency. What conditions must be met in order to achieve them?