请教OG第24题

If there is an oil-supply disruption resulting in higher international oil prices, domestic oil prices in open-market countries such as the US will rise as well, whether such countries import all or none of their oil.

If the statement in the passage concerning oil-supply disruptions is true, which of the following policies in an open-market nation is most likely to reduce the long-term economic impact on that nation of sharp and unexpected increases in international oil prices?

C.Suspending diplomatic relations with major oil-producing nations

D.Decreasing oil consumption through conservation

答案为什么是D不是C呢，为什么OG上说C是无关选项？？？