The answer will be 45 because it’s a right angle
We know is a horizontal line, so, if it passes through 1,-5, it also passes through "whatever", -5, like 20, -5 or 1000000, -5, or -100000000, -5 and so on.
so, let's pick another point say -7, -5, check the picture below, and let's check about the equation that runs through it,
I think it’s the 1st one because it’s close too what it is when I work it out