关于抑癌基因的叙述，下列哪项是正确的

A．是一类控制细胞生长的负调节基因

B．不存在于人类的正常细胞中

C．缺失或突变失活对细胞的增殖、分化无影响

D．肿瘤细胞出现时才进行表达

E．与癌基因表达无关

An investor purchased a 6 - year annual interest coupon bond one year ago. The coupon interest rate was 10 percent and the par value was $1000. At the time he purchased the bond, the yield to maturity was 8 percent. If he sold the bond after receiving the first interest payment and the yield to maturity continued to be 8 percent, his annual total rate of return on holding the bond for that year would have been:（）

A. 6.00%.

B. 9.95%.

C. 8.00%.