Crude oil prices dropped under $91 per barrel Thursday morning in a market made jittery by the death of Venezuelan leader Hugo Chavez. Venezuela has the largest accessible oil reserves in the world. A transition of power in the South American country puts oil traders on alert. Wednesday, the U.S. Energy Information Administration said domestic crude oil inventories rose by 3.8 million barrels to 381.4 million barrels in the week ending Friday. On the New York Mercantile Exchange, West Texas Intermediate crude oil pushed above $91 overnight, but then throttled back. In early trading, April delivery crude oil remained 37 cents higher than Wednesday's close at $90.87 per barrel. Gasoline shed 1.66 cents to $3.1169 a gallon. Home heating oil added 0.08 cents to reach $2.9708 a gallon. Natural gas dropped 1.5 cents to hit $3.469 per million British thermal units. At the pump, the national average price for a gallon of regular unleaded gasoline dropped from Wednesday's $3.727 per gallon to $3.719, the AAA Daily Fuel Gauge Report said.