C lacks any high level abstractions. All the abstractions it does offer are hiding register and stack slot assignments (as local variables), code entry point addresses (as function names), ALU instructions (as operators), branching (as control-flow statements), and address arithmetic (as pointer operations). All of these are low, machine-level abstractions.
C was never a high-level language, even from its first day. It was specifically intended as a portable assembly language, by someone used to coding assembly language, to use porting an OS coded in assembly language to a new target host.