Final answer:
A Trojan often comes from an 'Unknown' website or through deceptive email attachments. Users should be vigilant when downloading software and opening email attachments to avoid falling prey to these harmful programs.
Step-by-step explanation:
A Trojan is a type of malicious software that is often disguised within legitimate software. This can happen when software is downloaded from a c) Unknown website, which may not have the necessary security measures to ensure the software hasn't been tampered with. Additionally, Trojans can spread when a user is deceived into opening an email attachment that appears legitimate but contains the malicious code.
Hackers employ a variety of methods to break into websites, convince individuals to click on links, and trick them into divulging personal information. It's essential for users to be cautious about where they download software from, and be skeptical of email attachments, especially those that come from unexpected sources or seem unusual in any way.