I asked what Which answer choice best describes f(x)=x−12? The relationship shows a direct linear variation with a constant of variation of 12.

The relationship does not show a direct linear variation.

The relationship shows a direct linear variation with a constant of variation of 1.

The relationship shows a direct linear variation with a constant of variation of −12.

I was told that the answer was "the relationship shows a direct linear variation with a constant of variation of 1." But i chose that answer and it's wrong.