Machine Language

D.

The language closest to machine language is Assembly language.

Machine language is the lowest-level programming language understood directly by a computer's CPU. It is represented in binary code consisting of 0s and 1s. Programmers use other programming languages to write code, and then these languages are translated into machine language that computers can understand and execute.

Assembly language is a low-level programming language that is a one-to-one representation of machine language. It uses symbolic representations of the CPU's machine language instructions, called mnemonics, to make it easier for humans to write and understand code. Assembly language is specific to the processor architecture and hardware of a computer, making it non-portable across different systems.

Compiled languages, on the other hand, are high-level programming languages that are converted into machine language through a compilation process. The compiled code is executed directly by the computer's CPU. Examples of compiled languages are C, C++, and Java.

Scripted languages, like Python or JavaScript, are interpreted languages. The code is not compiled but is interpreted line-by-line at runtime. This makes them more flexible and portable, but also slower than compiled languages.

Query languages, like SQL, are used to retrieve data from databases. They are not programming languages, but rather a specific domain-specific language used for data manipulation and retrieval.

In summary, Assembly language is the programming language closest to machine language, as it uses symbolic representations of CPU instructions and has a one-to-one correspondence with machine code.