题目

Some say everyday miracles(奇迹) are predestined(注定的)----the right time for the appointed meeting. And it can happen anywhere. In 2001, 11-year-old Kevin Stephan was a bat boy for his younger brother's Little League team in Lancaster, New York. It was an early evening in late July. Kevin was standing on the grass away from the plate, where another youngster was warming up for the next game. Swinging his bat back and forth, giving it all the power an elementary school kid could give. The boy brought the bat back hard and hit Kevin in the chest. His heart stopped. When Kevin fell to th 某溶液中大量存在四种离子：NO3－、SO42－、H+、M，其物质的量之比为：n(NO3－)∶n(SO42－)∶n(H+)∶n(M)＝3∶1∶3∶1，则M可能为： ①Fe2+ ②Mg2+ ③Cl－ ④Ba2+ [　　] A． ①②④ B． ② C． ③ D． ①②