The type of contract where the buyer incurs opportunity cost but little or no additional cost risk is called （）.

A．fixed-price with incentive

B．firm-fixed-price

C．fixed-price with economic price adjustment

D．fixed-price with right of renewal

关于个人住房公积金的税收政策，下列说法中正确的是( )。

A．因为住房公积金是政策性资金，所以实行全部免税政策

B．个人提取住房公积金账户内的存储余额，按比例计征个人所得税

C．个人住房公积金作为储蓄性专项基金存款，其利息收入计征个人所得税

D．职工个人及其单位超过国家或地方政府规定的比例缴付的住房公积金，应将其超过部分并人个人当期的工资、薪金收入，计征个人所得税