精密称取苯巴比妥0.2099g，依法用硝酸银滴定液(0.1002mol/L)滴定至终点时消耗9.00ml，每1ml硝酸银滴定液(0.1mol/L)相当于23.22mg的苯巴比妥。苯巴比妥的含量为

A.94.4%

B.97.8%

C.98.6%

D.99.8%

E.100.2%