To their great fear, they found________in the heaviest snowfall they had ever had. [ ]

A. they were catching

B. themselves caught

C. they had caught  

D. themselves catching

根据《人民币银行结算账户管理办法》的有关规定，单位的法定代表人或主要负责人、住址以及其他开户资料发生变更时，应于3个工作日内书面通知开户银行并提供有关证明。（ ）