下述哪项才是上消化道内镜检查适应证

A．急性胃、食管炎症，尤其是腐蚀性、坏死性炎症

B．上消化道出血原因不明

C．上腹部有症状而X线检查阴性或疑有癌变但不能确诊者

D．X线发现溃疡或充盈缺损，性质不明

E．咽下困难、吞咽疼痛及胸骨后烧灼感疑有“食管性胸痛”

— _____ do you go hiking?

— Once a week. [ ]

A. How much

B. How often

C. How long

D. How soon