Your friends have some ideas about malware. Read the extract from a handbook and mark who is right.

What’s the difference between a virus, a worm, a Trojan and spyware?
All these types of malicious software, or malware, pose a serious threat to your computer
and data.
✓ A virus invades a computer and copies, deletes, or damages data.
✓ A worm is a virus that reproduces itself and spreads to other computers.
✓ A Trojan \(short for Trojan horse\) is a virus that, despite appearing to be good or helpful, actually destroys your data, damages your computer, and steals your personal information.
✓ Spyware is software that tracks your online activity, can launch numerous pop-up ads, and may steal your personal information or change your computer settings without your knowing.

• Jane: "Worms can copy themselves."
• Ann: "A Trojan can launch annoying advertisements".
• William: "Spyware can look helpful, but it's actually damaging".
• Olga: "Trojans, worms and spyware are all viruses".