—Maria, what're you going to be when you grow up? 

— A _________. I like to help doctors and take care of the sick. [ ]

A. nurse

B. reporter

C. teacher

D. policewoman

患者右上第一磨牙严重龋坏，拔除后送检物为囊壁样组织，镜下囊壁内衬复层扁平上皮，厚薄不均，有不规则上皮钉突形成；囊壁内主要为淋巴细胞、浆细胞，也混有中性粒细胞浸润，部分囊壁区域可见针形裂隙。上述描述为

A．慢性牙周炎
B．根尖周囊肿
C．牙槽脓肿
D．根尖周肉芽肿
E．慢性根尖周脓肿