Which of the following best describes adware?

Adware is best described as software that automatically displays or downloads advertising material. This type of software often generates revenue for its developers by displaying advertisements to users while they browse the internet or use other applications. Adware can sometimes affect the performance of devices by consuming bandwidth and system resources, but its primary characteristic is its intent to serve ads, often in ways that may not be obvious to users.

While adware may track user activity to serve targeted advertisements, it is not exclusively defined by that aspect. The key element of adware is its focus on generating advertising revenue rather than causing harm or replicating itself, which distinguishes it from other types of malware. The other options describe different categories of malicious software behaviors that do not align with the primary function of adware.