Answer:
a. Machine language
Step-by-step explanation:
Computers execute programs using machine language. Machine language instructions can be represented using binary or hexadecimal notation that can be understood by the computer. Assembly language, on the contrary, is a low-level programming language used by programmers. The language represents the machine code in a form that can be understood by humans. High-level languages are programming languages that are not limited to particular computer architecture and closely represent human language such as the C programming language.