By Trixie Sher Li Yap SINGAPORE (Reuters) – Oil prices firmed in Asian trade on Wednesday on falling U.S. crude inventory figures from API, a lower greenback and some optimism on the outlook for China’s demand and economy. A high likelihood that OPEC+ would leave output unchanged at its upcoming meeting limited gains. Brent crude futures had firmed 70 cents or 0.84% to $83.73 per barrel by 0732 GMT, while U.S. West Texas Intermediate (WTI) crude futures climbed 56 cents or 0.72% to $78.76 per barrel. The market is still in a contango structure, with forward month futures trading higher than th…