What is the primary role of the lexical analyser in the compilation process?

The lexical analyser, also known as the lexer or scanner, is the first phase of a compiler. Its primary role is to read the raw source code character by character and group them into meaningful sequences called tokens. These tokens represent fundamental elements of the programming language, such as keywords (e.g., 'if', 'while'), identifiers (variable names), operators (+, -), and literals. By converting the stream of characters into a structured sequence of tokens, the lexical analyser simplifies the subsequent parsing phase. Option C is correct because tokenization is the defining function of lexical analysis.

Option A (memory allocation) is typically handled by runtime systems or later compiler phases like code generation. Option B (constructing syntax trees) is the responsibility of the parser, which operates on tokens produced by the lexical analyser. Option D (producing machine-level instructions) occurs during code generation, which is one of the final stages. Therefore, breaking source code into tokens is the exclusive and primary task of the lexical analyser.