_____ suddenly occurred to me _____ I had to attend an important meeting in Shanghai the next day.

A．It; which

B．What; that

C．What; which

D．It; that

40岁男性，股骨下端疼痛，膝关节活动轻微受限。查体：股骨下端偏外侧局限性隆起，压痛，皮温略高。x片：股骨外侧髁可见偏心性生长的骨吸收病灶，皮质向外膨隆，变薄，无骨膜反应。诊断为

A．骨纤维异样增殖症

B．骨巨细胞瘤

C．嗜酸性肉芽肿

D．内生软骨瘤

E．骨囊肿