Which one of the following is a good defense against worms?

A.
Differentiating systems along the lines exploited by the attack.

B.
Placing limits on sharing, writing, and executing programs.

C.
Keeping data objects small, simple, and obvious as to their intent.

D.
Limiting connectivity by means of well-managed access controls.

Explanation:
Take as general information regarding worms
“Although the worm is not technically malicious, opening the attachment allows the file to copy
itself to the user’s PC Windows folder and then send the .pif-based program to any e-mail address
stored on the hard drive.
Ducklin said the huge risks associated with accepting program files such as .pif, .vbs (visual basic
script) or the more common .exe (executable) as attachments via e-mail outweighs the usefulness
of distributing such files in this manner.
“There’s no business sense for distributing programs via e-mail,” he said.
To illustrate the point, Ducklin said six of the top 10 viruses reported to Sophos in April spread as
Windows programs inside e-mails.”
http://security.itworld.com/4340/030521stopworms/page_1.html