Linear equations in two variables SAT question

Choice D is correct. An equation defining a line in the xy-plane can be written in the form $y=mx+b$, where $m$ represents the slope and $(0,b)$ represents the y-intercept of the line. It’s given that line $k$ passes through the point $(0,-5)$; therefore, $b=-5$. The slope, $m$, of a line can be found using any two points on the line, $(x_1,y_1)$ and $(x_2,y_2)$, and the slope formula $m=\frac{y_2-y_1}{x_2-x_1}$. Substituting the points $(0,-5)$ and $(1,-1)$ for $(x_1,y_1)$ and $(x_2,y_2)$, respectively, in the slope formula yields $m=\frac{(-1-(-5))}{(1-0)}$, or $m=4$. Substituting $4$ for $m$ and $-5$ for $b$ in the equation $y=mx+b$ yields $y=4x-5$. 

Choice A is incorrect and may result from conceptual or calculation errors.

Choice B is incorrect and may result from conceptual or calculation errors.

Choice C is incorrect and may result from conceptual or calculation errors.