Crude oil prices are about to end this week with another gain, driven by optimism about demand rebound in China. It was that same optimism that yesterday pushed prices to the highest close since the start of December, Reuters reported. Brent crude gained $1.18 per barrel on Thursday and West Texas Intermediate added $0.85 to top $80 per barrel for the first time in weeks. “Prices gained as China optimism continued to reign,” Charu Chanana, market strategist at Saxo Capital Markets, told Bloomberg today. “Reports that China’s…