The answer is Malware -- Though in my humble opinion, that question is worded awfully. Disorder? I am surprised they did not use the word 'malfeasance' instead.
Spam is unwanted email
Spyware is can be considered 'malware' but most of the time we call it Potential Unwanted Programs (PUP). Spyware is an application that tracks and or logs what you type and where you go on the computer/internet.
Antivirus software is what is supposed to be the last line of malware defense.
