A、stuDy oF thunDErClouDs ovEr thE northAtlAntiC showED thAt lightning oCCurrED only whEn thE Air tEmpErAturE______.
A、ArounD thE ClouD wAs BElow FrEEzing
B．ArounD thE ClouD wAs ABovE FrEEzing
C．ABout thE ClouD wAs lowEr thAn thE tEmpErAturE BElow thE ClouD
D．oF thE ClouD wAs ABovE FrEEzing