Assembly language is a low-level programming language that uses mnemonics or symbolic names to represent machine code instructions. Machine code is the binary code that is directly executed by the processor. Assembly language is the closest to machine code among the options given because it has a one-to-one correspondence with machine code instructions. Query language, scripting language, and markup language are not programming languages that are close to machine code because they use higher-level syntax or commands that need to be translated or interpreted by other programs before execution. References: CompTIA IT Fundamentals+ Study Guide: Exam FC0-U61, Second Edition, Chapter 4: Programming Concepts and Data Structures, page 139.