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 Q5 and Qd are quantities of natural gas in billion cubic feet, P is the price of natural gas in USD/thousand cubic feet, and P0 is the price of oil, equal to 60 USD/barrel. Oil and natural gas are: 0 unrelated goods in consumption 0 substitutes in consumption 0 not enough information to know 0 complements in consumption