In computer programming, syntax errors in source code are typically detected by which program component?

Introduction / Context:
When writing programs, developers must follow the syntax rules of the programming language. If a programmer makes a mistake such as missing a semicolon or using a keyword incorrectly, the program will not run correctly. These mistakes are called syntax errors. This question checks whether learners know which component or tool in the software environment is responsible for detecting syntax errors before or during execution.

Given Data / Assumptions:

• The question is about syntax errors in source code.
• Options include Interpreter, ALU, Logic Unit, Control Unit, and a general distractor.
• We assume basic understanding of the difference between hardware components and language processing tools.
• We consider typical scenarios where a program is interpreted or compiled.

Concept / Approach:
Syntax errors occur when the source code does not follow the grammatical rules of the programming language. These errors are caught by software tools that read and translate the source code, such as compilers and interpreters. An interpreter reads high level language statements, checks them for correctness, and executes them line by line. Hardware units such as the Arithmetic Logic Unit (ALU) and Control Unit operate at the machine instruction level and assume that the incoming instructions are already valid. Therefore, the approach is to identify which option refers to a software component that parses and executes code and can therefore detect syntax errors.

Step-by-Step Solution:
Step 1: Recall that an interpreter translates and executes high level language statements step by step.Step 2: Understand that during this process, the interpreter must first check whether each statement follows the correct syntax.Step 3: Recognise that hardware components such as the ALU and Control Unit work with machine level instructions, not with the original high level source code.Step 4: Compare the options and note that Interpreter is the only one that acts directly on source code in many interpreted languages.Step 5: Conclude that Interpreter is the correct choice for detecting syntax errors in this context.

Verification / Alternative Check:
To verify, imagine writing a program in a language like Python or JavaScript, which is often interpreted. If you omit a colon or closing bracket, the interpreter immediately displays a syntax error message and stops execution. In compiled languages, the compiler performs a similar role, but the question provides Interpreter as the closest correct option. Neither the ALU nor the Control Unit displays error messages about missing semicolons or wrong keywords, since they only process binary instructions that have already passed through the language processing stage. This practical experience supports selecting Interpreter.

Why Other Options Are Wrong:
The ALU (Arithmetic Logic Unit) performs arithmetic and logical operations on binary data and does not inspect high level source code. The Logic Unit in the context of hardware is part of the ALU and also works only with machine level instructions. The Control Unit directs the operation of the processor by fetching, decoding, and executing instructions but assumes the instructions are already valid. None of these is incorrect because syntax checking is done before the code reaches these hardware components. Therefore, Interpreter is the most appropriate answer from the list.

Common Pitfalls:
Students may confuse hardware units with software tools and think that because the processor executes instructions, it also checks syntax. Another pitfall is forgetting that syntax is a property of high level languages and that by the time instructions reach the hardware level, they have been translated into machine code. Remembering that interpreters and compilers enforce language rules while hardware executes the resulting instructions helps keep these roles clear.

Final Answer:
Syntax errors in source code are typically determined by the Interpreter.