Scenarios A and B are identical in every respect (e.g. demand function, initial resource stock, and extraction cost function), except for the following: in Scenario A, a backstop with constant marginal cost b is available at time t = 0; in Scenario B it is known at time t = 0 that the backstop will not become available until t = 49. (a) Suppose that in Scenario A, the backstop begins to be used at time t = 50. What, if any, is the difference in extraction trajectories in the two scenarios? Explain your answer briefly. (b) Scenario C involves uncertainty. The time at which the backstop will become available is a random variable with expected value t = 50. (For example, with probability 0.5 the backstop becomes available at t = 48 and with probability 0.5 it becomes available at t = 52; for this example, at a moment after t = 48 the market knows which world it inhabits. This numerical example might help make the question less abstract, but you do not need numbers to answer this question. The point of this question is to encourage you to use concepts that we discussed to draw conclusions about a situation that we have not discussed.) Compare the equilibrium in Scenario C with those in Scenarios A and B and justify your conjectures