This question doesn't have to have an answer. The author of TFA apparently believes that a low-level language is one that effectively and clearly exposes the execution model of the hardware to the programmer. Under this definition, no widespread language (except assembly) is truly low-level, and possibly none are.

Which, for what it's worth, is also what I was taught in school. C was consistently described as a high-level language by my professors, even if it is "lower-level" than almost everything else.