A computer virus that actively attacks an anti-virus program or programs in an effort to prevent detection is…

Worm
Retrovirus
Trojan
Ghost virus

The answer is: A. Worm.

A worm is a type of malware that can replicate itself and spread from one computer to another without the need for human interaction. Worms can damage files, steal data, and even take control of computers.

Antivirus programs are designed to detect and remove viruses, but worms can be very difficult to detect. This is because worms often hide themselves in legitimate files or programs. Worms can also disable antivirus programs, making it even more difficult to remove them.

There are a number of things you can do to protect yourself from worms, including:

  • Keep your operating system and software up to date.
  • Use a firewall.
  • Install antivirus software and keep it up to date.
  • Be careful about what files you open and what links you click on.
  • Be aware of the latest threats and how to protect yourself from them.

If you think your computer may be infected with a worm, you should run a scan with your antivirus program. If the scan detects a worm, you should follow the instructions provided by your antivirus program to remove it.

Here is a brief explanation of each option:

  • A worm is a type of malware that can replicate itself and spread from one computer to another without the need for human interaction. Worms can damage files, steal data, and even take control of computers.
  • A virus is a type of malware that can replicate itself and spread from one computer to another, but it requires human interaction to spread. Viruses can damage files, steal data, and even take control of computers.
  • A Trojan horse is a type of malware that disguises itself as a legitimate program. Once installed on a computer, a Trojan horse can steal data, damage files, or even take control of the computer.
  • A ghost virus is a type of virus that can hide itself from antivirus programs. Ghost viruses are often used to spread other types of malware, such as worms and Trojan horses.