That day everyone wondered _____ the baby of four went to her mother’s office.

A．how was it that

B．how it was that

C．how was it

D．how was that

患者女性，29岁，右上第二磨牙残根，慢性根尖周炎。拔除腭侧根过程中，牙根突然消失，捏鼻鼓气时拔牙窝内有气体溢出

如X线片显示患者为低位上颌窦，移位的牙根已进入上颌窦，但仍位于拔牙窝附近，此时最佳处理方法为（）

A.密切观察，1周后复诊

B.刮匙搔刮取根

C.从穿孔处冲洗

D.于穿孔处开窗取根

E.上颌窦根治术