A.≥90% B.≥95% C.≥97% D.≥98% E.≥99.9%
A.(2.1±2.0)×108 B.(2.1±2.0)×109 C.(2.1±2.0)×107 D.(2.1±2.0)×106 E.(2.1±2.0)×105
A.99% B.97% C.95% D.92% E.90%