Answer:
Option B.
Explanation:
Vertical line: All lines that are parallel to y-axis are called vertical lines. Th are defined as x=a and the slope of a vertical line is ∞.
Horizontal line: All lines that are parallel to x-axis are called horizontal lines. They are defined as y=b and the slope of a horizontal line is 0.
Consider the equation
![y=-6](https://img.qammunity.org/2020/formulas/mathematics/high-school/jtgzgkbrak9li08bo9xh9fb4rbvajxoi43.png)
This equation in the form of y=b. So, the graph of the equation is a horizontal line with a slope of zero.
Therefore, the correct option is B.