In the given question some information is missing that is the option of the question, which can be described as follows:
a. Firewalls.
b. Mirror disc.
c. Threat from the backdoor.
d. blended threat.
It includes bugs malicious content like malware, grubs, and many other scripts. It helps in remembering things when you combine multiple tasks in a processor to help learn, Its combination of stuff is produced, and other choices were false that can be described as follows:
In option a, It provides security to malicious, that's why it is wrong.
In option b, It is part of storage system, that's why it is incorrect.
In option c, It bypasses the normal security system, that's why it is wrong
Using key escrow we are able to recover data if passphrase is forgotten. this technique uses a bypass link to get all the keys to the system only if it is an authorized entry.