Many of the big world sports events are _______by wealthy big companies, who hope to advertise their  companies or their products.     [ ]

A. organized    

B. arranged      

C. hosted    

D. sponsored

女性，24岁，主诉：用牙线清洁牙齿时牙龈有时出血。检查：牙龈 * * 轻度充血、水肿，PD：2～3mm，未及附着丧失。此患者最可能的诊断是

A．边缘性龈炎
B．牙间 * * 炎
C．青春期龈炎
D．青少年牙周炎
E．急性坏死性龈炎