Choice A is the correct answer. Slope 0 means horizontal.

1. Horizontal: Equation is $y = k$.
2. Point: The y-coordinate is 5.
3. Equation: $y = 5$.

💡 Strategic Tip: Match the variable to the coordinate value. Horizontal $\rightarrow y$. Vertical $\rightarrow x$.

Choice B is incorrect because it is vertical. Choice C is incorrect because it uses the x-coordinate. Choice D is incorrect because it mixes variables.