这个题目太坑了。一般来说 Clone 是指 create from 的方式。

但是这里说是 with RMAN，其实指的是 duplicate 的模式。

这样的话，答案就呼之欲出了。

A、Only one PDB can be cloned at a time.

这个是错误的，duplicate 可以同时克隆复制多个 PDB，例如：

DUPLICATE DATABASE TO cdb1 PLUGGABLE DATABASE pdb1,pdb3,pdb4;

E、A non-CDB can be cloned into a PDB.

这个是错误的。这是一个文字游戏，注意不要被英文误导。

Non-CDB 可以被 Clone into a CDB，而不是融入一个 PDB。

我认为正确答案是：

C、Two or more PDBs can be cloned with the same command.
D、A user with SYSDBA or SYSBKUP must be logged in with RMAN to the non-CDB being cloned when cloning a non-CDB.
F、The target and auxiliary instance passwords must be the same.

纠正，根据文档：
A、Only one PDB can be cloned at a time.
是正确选项。

Duplicating a PDB to an existing CDB is subject to certain restrictions.

Only active database duplication is supported.

Only the following clauses of the DUPLICATE command are supported: NORESUME, DB_FILE_NAME_CONVERT, SECTION SIZE, and USING COMPRESSED BACKUPSET.

The following clauses of the DUPLICATE command are not supported: SPFILE, NO STANDBY, FARSYNC STANDBY, and LOG_FILE_NAME_CONVERT.

Duplicating a PDB to a CDB that is a standby database is not supported.

Only one PDB can be duplicated at a time.

Partial PDB duplication is not supported, only complete PDB duplication is supported. For example, you cannot include or exclude specific tablespaces while duplicating a PDB.

Duplicating a non-CDB as a PDB in an existing CDB is not supported.

Duplicating PDBs that contain TDE-encrypted tablespaces is not supported.