What is a significant challenge associated with computer viruses?

The significant challenge associated with computer viruses lies in their ability to replicate and the ease with which they can be transmitted, particularly via email. Viruses often attach themselves to legitimate files or emails and are sent to contacts in a user’s address book, making it simple for them to spread rapidly across networks. This characteristic poses a substantial risk to both individual users and organizations, as it can lead to widespread infection within a short period, compromising data integrity and system security.

Additionally, the replication behavior of viruses means they can multiply without direct human interaction, which complicates prevention and containment efforts. As users unknowingly forward infected files or emails, the virus propagates, increasing the difficulty of detection and removal. This ability to spread quickly is one of the main reasons that computer viruses remain a persistent threat in cybersecurity.

The other options highlight misconceptions or limited scenarios regarding virus behavior and management that do not encompass the broader challenges presented by computer viruses. For example, while some viruses can be transmitted through USB drives, the claim that this is their sole transmission method is inaccurate. Manual deletion is not always necessary or effective for all viruses, and they are not typically characterized by easy diagnosability, as many viruses can operate stealthily without notable symptoms.