Crude oil prices held above $87 a barrel Monday as the possibility of an economic stimulus program in China was countered by a stronger U.S. dollar. Traders also focused on supply issues in the Middle East, as Iran threatened to block oil movement through the Straits of Hormuz in response to an international embargo over the possibility that Iran is developing nuclear weapons. In early trading, light, sweet crude for August delivery added 11 cents to $87.21 a barrel on the New York Mercantile Exchange. Henry Hub natural gas was shed 6.7 cents to $2.807 per million British thermal units. Home heating oil was up 1.48 percent to $2.803 per gallon. Reformulated blendstock gasoline was up 1.69 cents to $2.833 a gallon. At the pump, the national average price of unleaded gasoline was $3.396 per gallon Monday, unchanged from Sunday, AAA said.