$15$ When a user turns on the PC on Wednesday, the PC displays a message indicating that all of the user files have been locked. In order to get the files unencrypted, the user is supposed to send an email and include a specific ID in the email title. The message also includes ways to buy and submit bitcoins as payment for the file decryption. After inspecting the message, the technician suspects a security breach occurred. What type of malware could be responsible?

Trojan

adware

spyware

ransomware