Suppose that the inverse demand and supply functions for natural gas are given by: P = 8 + Qs +0.1Po and P = 16 - Qd +0.1Po, where Qs and Qd are quantities of natural gas in billion cubic feet, P is the price of natural gas in USD/thousand cubic feet, and Po is the price of oil, equal to 60 USD/barrel. If a price ceiling is set at P' = 16 USD/tcf, then the dead weight loss is: O 6 m USD OO O 4 m USD 0 9 m USD