Post office protocol $(POP)$ is a message access protocol which is used to extract message for client. In this regard, which of the following are true?

$(A)$ POP has two modes, Delete mode and keep mode

$(B)$ In Delete mode, mail is deleted from mail box after each retrieval

$(C)$ In Delete mode, mail is deleted from mail box before each retrieval

$(D)$ In keep mode, mail is deleted before retrieval

$(E)$ In keep mode, mail remains in mail box after retrieval

Choose the correct answer from the options given below:

POP is used by a client to download emails from the mail server.

POP has two modes:

Delete mode and keep mode.

In Delete mode, after the client retrieves the mail, the mail is deleted from the mailbox.

So, statement $(B)$ is true.

In Delete mode, mail is not deleted before retrieval.

So, statement $(C)$ is false.

In keep mode, mail is not deleted after retrieval.

The mail remains in the mailbox even after retrieval.

So, statement $(E)$ is true.

Statement $(D)$ is false because in keep mode mail is not deleted before retrieval.

Therefore, true statements are $(A)$, $(B)$ and $(E)$.