In the single-user modal wa assume that there's a single aactor making decisions about how to un water Coraldar the case In the graph, which shows the marginal nat banafit cure for tha sactor with total available water W=60 units. What would be the efficient use of water for the sector? P MNB Q W=50 75 O A. 50 unhs O B. 75 unhs O C. 25 units O D. 60 unitsDue to the open access problem with the allocation of groundwater, groundwater pumping costs will too rapidly, and initial prices will be too O A. fall; low O B. rise: low O C. fall; high O D. rise: high