create table t（id int not null, a int default 0, b int default 0, c int default 0, primary key（id）, key idx_a_b（a, b））;下面语句能够利用到索引的是（）

A. select b from t where a=10;

B. select * from t where a=10 and id=100;

C. select * from t where a=10 and b>100;

D. select * from t where a>10 and b < 100;

E. select * from t order by b limit 10;