In basic computer security, which of the following terms refers to a type of malicious software (malware) that disguises itself as a legitimate program to trick users into installing it?

Introduction / Context:
This question belongs to the area of basic computer literacy and information security. Modern users frequently encounter different types of malicious software, commonly called malware. Understanding terms such as virus, worm, Trojan and firewall helps you to recognise common threats and protect your devices. Here, the focus is on a type of malware that pretends to be useful or harmless software so that users willingly install it on their own systems.

Given Data / Assumptions:

• The question is about computer malware and information security.
• The malicious program disguises itself as a legitimate or helpful program.
• Once installed, it can perform harmful actions such as stealing data or opening backdoors.
• We are asked to select the correct term from the given options.

Concept / Approach:
In computer security terminology, a Trojan, often called a Trojan horse, is a type of malware that appears to be a normal, helpful or attractive application but actually contains hidden malicious code. The name comes from the famous Trojan horse story in Greek mythology, where a wooden horse was used to secretly bring soldiers inside the walls of Troy. The other words in the options, such as Spartan, Persian, Roman and firewall, do not describe this specific kind of disguised malware.

Step-by-Step Solution:
Step 1: Recall that malware includes viruses, worms, Trojans, spyware, ransomware and other harmful programs. Step 2: Identify the defining feature in the question: the program looks legitimate but hides malicious intent. Step 3: Connect this behaviour with the well known term Trojan, which acts like a friendly program but attacks from the inside after installation. Step 4: Note that Spartan, Persian and Roman are names connected with ancient peoples or empires but have no standard technical meaning in computer security. Step 5: Recognise that a firewall is a security tool that protects networks and devices by filtering traffic, so it is not a type of malware. Step 6: Conclude that the only option that correctly names this category of disguised malware is Trojan.

Verification / Alternative check:
If you check any basic information security textbook or online guide, you will find that a Trojan or Trojan horse is defined as a malicious program that misleads users of its true intent. It often arrives as an email attachment, a software crack, a fake utility or a game. Once executed, it can install additional malware, log keystrokes or create remote access for attackers. This matches the description in the question and confirms that Trojan is the right answer.

Why Other Options Are Wrong:
Spartan and Persian are not standard terms for malware categories in computer science and therefore do not match the definition. Roman similarly has no special meaning in information security and is only a historical or cultural term. Firewall is a defensive mechanism that filters network traffic; it is intended to protect a system rather than harm it.

Common Pitfalls:
A possible mistake is to choose firewall simply because it is a familiar technical word, without noticing that the question clearly refers to malware, not to protection tools. Another pitfall is to think that any historical term like Spartan or Persian might be used in security, but in reality Trojan is the established technical term. Always link the description in the question with the textbook definition of each option.

Final Answer:
The term for malware that disguises itself as a legitimate program is Trojan.