Recently, Frank's Computer Has Slowed Down Dramatically

Multiple Choice

Recently, Frank's computer has slowed down dramatically. He has also noticed that the time on the computer is not accurate. Frank has run several antivirus scans, but has not found an issue. Today while surfing the web, he was redirected several times to a website that he did not request. Then a BSOD error occurred on his computer, and when he turned on his computer, the antivirus software was disabled.  
What kind of malware could be causing the issues on Frank's computer?

A) Zombie
B) Rootkit
C) Spyware
D) Ransomware