Which two actions are taken by SMTP if the destination email server is busy when email messages are sent? (Choose two.)

Question:
Which two actions are taken by SMTP if the destination email server is busy when email messages are sent? (Choose two.)

• SMTP sends an error message back to the sender and closes the connection.
• SMTP tries to send the messages at a later time.
• SMTP will discard the message if it is still not delivered after a predetermined expiration time.
• SMTP periodically checks the queue for messages and attempts to send them again.
• SMTP sends the messages to another mail server for delivery.

Exam with this question: CCNA 1 (v5.1 + v6.0) Chapter 10 Exam Answers