对于需要提供账户凭证原件的个人网上银行业务，柜员必须验证账户磁道信息和密码，保证账户真实性。

Which condition is necessary for a substance to burn?（）

A.The temperature of the substance must be equal to or above its fire point

B.The air must contain oxygen in sufficient quantity

C.The mixture of vapors with air must be within the explosive range

D.All of the above