c) What is the magnitude of the total (gross) annual benefits associated with this (efficient allocation) policy? d) What is the magnitude of the total (gross) annual costs associated with this (efficient allocation) policy? e) What is the magnitude of the net annual benefits associated with this (efficient allocation) policy? f) If it turns out that the marginal cost of preservation is only $20,000 per mile per year, how many miles of the river would be preserved in an efficient allocation? g) What if substitute sites were available to beneficiaries, and so it was found that their demands were substantially more elastic, i.e. their individual demand functions for river preservation are Q = 40 - 1.213 In this case, with the original marginal costs of preservation of $25,000 per mile per year, how many miles of the river would be preserved in an efficient allocation