Assembly is not one language (even if they all look very alike). It's a collection of opcodes or mnemonics specific to a specific architecture with a specific instruction set that map to the later. Even then writing assembly for MASM, TASM, WASM, or WhateverASM for Linux, Windows, or Winux (or whatever) can and will probably differ in structure and in the specific mnemonics used.

There's machine code, low level languages which are basically the plethora of different Assembly languages, and high level languages which provide abstractions to either or both of the former languages and resemble the actual written language. Putting C in the low level languages rank is doing a disservice to the language and not taking into account the bunch of people that program (for example) embedded devices in whatever architecture they're using.