Final answer:
Viruses, worms, phishing attacks, spear phishing attacks, and DoS are types of software threats that can harm information systems by spreading malware or interrupting services.
Step-by-step explanation:
Viruses, worms, phishing attacks, spear phishing attacks, and DoS (Denial of Service) are all examples of b) Software threats. These malicious activities pose significant risks to individuals and organizations by compromising the integrity, confidentiality, and availability of information systems. A virus can self-replicate and spread to other programs and files, a worm can propagate without human intervention, phishing is a deceptive attempt to obtain sensitive information typically through emails, spear phishing is a targeted version of phishing, and DoS is an attack meant to shut down a machine or network, making it inaccessible to its intended users.