What fallacy does this illustrate phrase " Everyone knows that taxes are bad for the economy."?

The correct answer to the following question will be "Argument Ad Populum".

Explanation:

An argumentum ad populum seems to be a specious argument which argues that perhaps a concept would have to be valid because it will be believed by so many or by several people, sometimes accurately embedded as: "If many think so, it's so".The typical implicit fallacy of argumentum ad populum is generally defined as the mistake perpetrated by aiming an emotional argument to either the "gallery" or "citizens" emotions or enthusiasm to gain approval to such an argument not properly backed by adequate evidence.

Therefore, it's the right answer.