Which of the following sequence of events best describes an online intrusion?

A. Malware enters the device, and then opens a backdoor, which opens a communications link on the device that a hacker can exploit.
B. A backdoor is opened on the device locally, which allows malware to be loaded onto the device by a hacker.
C. A USB drive containing a trojan is inserted into a device, which opens a backdoor allowing a hacker access to the device.
D. None of the above.

Answer: A