Choice A is the correct answer. The x-axis is horizontal.

1. Parallel: A line parallel to the x-axis must also be horizontal.
2. Form: Horizontal lines have the equation $y = k$.
3. Match: $y = 7$ fits.

💡 Strategic Tip: The x-axis itself is the line $y=0$.

Choice B is incorrect because it is vertical (parallel to y-axis). Choice C is incorrect because it is diagonal. Choice D is incorrect because it is diagonal.