What is the primary difference between virus and worm?

• A. A worm has the ability to self-propagate from the infected computer of the user to other computers.
• B. The worm is usually written by a cracker - script bunnies do not have the skill of worm program development
• C. Viruses are very harmful for the computers it infects; Worm is not such a serious problem.
• D. Antivirus is effective for fighting software, not for fighting worms
• E. None of the above