What is the primary function of LEX in the context of lexical analysis in…

LEX is a lexical analyzer generator tool used in compiler construction that takes regular expressions as input to generate efficient scanners (lexical analyzers). Its primary function is to convert source code into a stream of tokens by matching patterns defined via regular expressions. This makes Option C the correct answer because LEX automates scanner generation, handling token recognition and whitespace skipping without manual coding. Option A is incorrect because code optimization occurs in later compiler phases, not lexical analysis. Option B describes YACC or Bison, which handle context-free grammars for parsing, not lexical analysis. Option D is also incorrect as abstract syntax trees are constructed during semantic analysis or parsing, not by LEX. Thus, LEX specifically focuses on tokenization using regular expressions.