In case Customs duties are short-levied or not levied on import or export, the Customs may, within ______ after the date of payment of Customs duties or the date of release of the goods, recover the amount of Customs duties short-levied or not levied.

A. six months
B. one year
C. two years
D. four years

辛烷值是表示（）的理化指标。它等于与其抗爆性相同的标准燃料中含异辛烷的体积百分数。