b) Person 1 will choose g1 taking into account their own benefits, but ignoring everyone else's. Write down the marginal benefit function that they use to make decisions, and substitute our definition of g = g1 + G_1 so you have marginal benefits as a function of 91 (which is a choice) and G_1, which person 1 takes as fixed. Write down the relevant marginal cost curve as well, using the gi and G_1 notation. (1 point)