Prices vary widely across the country, with California’s average at $6.425 a gallon. U.S. gasoline prices are ticking up after a roughly 100-day decline, threatening to inflict new pain on consumers who have been grappling with widespread inflation for more than a year. Maintenance at fuel-making plants, more demand for gasoline and tight fuel supplies have contributed to a 14-day run of increasing gasoline prices. A gallon of regular averaged about $3.831 on Wednesday, according to OPIS, an energy-data firm that is part of Dow Jones & Co., publisher of The Wall Street Journal.