A User Is Unable to Open a File That Has

A user is unable to open a file that has a grayed-out icon with a lock. The user receives a pop-up message indicating that payment must be sent in Bitcoin to unlock the file. Later in the day, other users in the organization lose the ability to open files on the server. Which of the following has MOST likely occurred? (Choose three.)

A) Crypto-malware
B) Adware
C) Botnet attack
D) Virus
E) Ransomware
F) Backdoor
G) DDoS attack