A: The APPEND keyword tells SQL*Loader to preserve any preexisting data in the table. Other options allow you to delete preexisting data, or to fail with an error if the table is not empty to begin with.
B (not D):
Note:
* SQL*Loader-00210: first data file is empty, cannot process the FIELD NAMES record
Cause: The data file listed in the next message was empty. Therefore, the FIELD NAMES FIRST FILE directive could not be processed.
Action: Check the listed data file and fix it. Then retry the operation
E:
* A comma-separated values (CSV) (also sometimes called character-separated values, because the separator character does not have to be a comma) file stores tabular data (numbers and text) in plain-text form. Plain text means that the file is a sequence of characters, with no data that has to be interpreted instead, as binary numbers. A CSV file consists of any number of records, separated by line breaks of some kind; each record consists of fields, separated by some other character or string, most commonly a literal comma or tab. Usually, all records have an identical sequence of fields.
* Fields with embedded commas must be quoted.
Example:
1997,Ford,E350,"Super, luxurious truck"
Note:
* SQL*Loader is a bulk loader utility used for moving data from external files into the Oracle database.

Explanation/Reference:

Explanation
* The CREATE DATABASE ... ENABLE PLUGGABLE DATABASE SQL statement creates a new CDB. If you do not specify the ENABLE PLUGGABLE DATABASE clause, then the newly created database is a non-CDB and can never contain PDBs.
Along with the root (CDB$ROOT), Oracle Database automatically creates a seed PDB (PDB$SEED). The following graphic shows a newly created CDB:

* Creating a PDB
Rather than constructing the data dictionary tables that define an empty PDB from scratch, and then populating its Obj$ and Dependency$ tables, the empty PDB is created when the CDB is created. (Here, we use empty to mean containing no customer-created artifacts.) It is referred to as the seed PDB and has the name PDB$Seed.
Every CDB non-negotiably contains a seed PDB; it is non-negotiably always open in read-only mode. This has no conceptual significance; rather, it is just an optimization device. The create PDB operation is implemented as a special case of the clone PDB operation.

E: Performance is improved by load balancing across multiple network interfaces (if available).
Note:
* To enable Direct NFS Client, you must replace the standard Oracle Disk Manager (ODM) library with one that supports Direct NFS Client.
Incorrect:
Not A: Direct NFS Client is capable of performing concurrent direct I/O, which bypasses any operating system level caches and eliminates any operating system write-ordering locks Not B:
* To use Direct NFS Client, the NFS file systems must first be mounted and available over regular NFS mounts.
* Oracle Direct NFS (dNFS) is an optimized NFS (Network File System) client that provides faster and more scalable access to NFS storage located on NAS storage devices (accessible over TCP/IP).
Not D: Direct NFS is provided as part of the database kernel, and is thus available on all supported database platforms - even those that don't support NFS natively, like Windows.
Note:
* Oracle Direct NFS (dNFS) is an optimized NFS (Network File System) client that provides faster and more scalable access to NFS storage located on NAS storage devices (accessible over TCP/IP). Direct NFS is built directly into the database kernel - just like ASM which is mainly used when using DAS or SAN storage.
* Oracle Direct NFS (dNFS) is an internal I/O layer that provides faster access to large NFS files than traditional NFS clients.