Which of the following is a common type of malware?

The option indicating "All of the above" is correct because it encompasses multiple types of malware that are prevalent in today's digital environment. Ransomware is malicious software designed to block access to a system until a ransom is paid, thus posing significant threats to both individual users and organizations by holding data hostage.

A Trojan Horse, another form of malware, disguises itself as legitimate software to trick users into installing it. Once executed, it can allow unauthorized access to the user's system and data, leading to potential data theft or damage.

Additionally, viruses are a well-known type of malware that can replicate themselves and spread to other computers. They can corrupt or delete files, compromise system performance, and create various security issues.

Recognizing that all these options represent different, yet common forms of malware helps in understanding the variety of threats that exist. Each type has its own method of attack and impact, underlining the importance of cybersecurity measures to protect against them.