（323）What is the correct order of the following commands if you wanted to restore datafile 4, which was accidentally removed from the file system?

a. sql 'alter database datafile 4 online';

b. restore datafile 4;

c. recover datafile 4;

d. sql 'alter database datafile 4 offline';

e. startup

f. shutdown

A. a, c, b, d

B. d, b, c, a

C. f, d, b, c, a, e

D. c, a, b, d, f

E. a, b, d, e

答案：（B）

解析：

不需要关闭数据库实例