By Arathy Somasekhar HOUSTON (Reuters) -Global benchmark Brent crude tumbled $7 on Tuesday to settle below $100 a barrel for the first time in three months on a strengthening dollar, demand-sapping COVID-19 curbs in top crude importer China, and rising fears of a global economic slowdown. The sharp drop followed a month of volatile trading in which investors have sold oil positions on worries that aggressive interest rate hikes to stem inflation will spur an economic downturn that will pull the rug out from oil demand. Brent crude futures settled $7.61, or 7.1% lower, at $99.49 a barrel, its l…