There is a real possibility that these animals could be frightened, ______ a sudden loud noise. [ ]

A. should there be

B. being there

C. there was

D. there having been

男性，40岁，近2个月以来，发作性血压升高达28/16kPa(210/120mmHg)，伴心悸，大汗、头痛，症状持续2小时后可自行缓解，血压恢复正常。

本病例最可能的诊断为

A．原发性高血压
B．高血压危象
C．嗜铬细胞瘤
D．皮质醇增多症
E．主动脉缩窄