Which of the following is a computer worm that caused a denial of service on some Internet hosts and dramatically slowed down general Internet traffic?

Code Red was a worm targeting IIS web servers via a buffer overflow in the ISAPI extension, known for defacing websites and launching DDoS attacks against specific IP addresses, not for broadly slowing global Internet traffic.

Beast is a remote access trojan (RAT) designed to give attackers backdoor control over infected systems, not a worm responsible for Internet-wide denial of service.

Klez was an email-propagating worm and virus that spread via infected attachments and exploited Outlook vulnerabilities, but it did not cause significant denial of service or global Internet slowdown.

SQL Slammer (also called Sapphire) exploited a buffer overflow vulnerability in Microsoft SQL Server 2000 via UDP port 1434. It spread so rapidly that it doubled in size every 8.5 seconds, generating enough traffic to cause packet loss and denial of service on numerous Internet hosts while dramatically slowing overall Internet traffic.