Answer:
A
Step-by-step explanation:
In standard form, an ellipse's major axis is indicated by the [tex]a^{2}, b^{2}[/tex] terms like this:
[tex]\frac{{(y-k)}^{2}}{a^{2}}+\frac{(x-h)^{2}}{b^{2}}, a>b[/tex]
[tex]\frac{{(x-h)}^{2}}{a^{2}}+\frac{(y-k)^{2}}{b^{2}}, a>b[/tex]
In the top equation, the vertical axis is primary and in the second the horizontal axis is primary. That's a bit more info than the question asked, but I thought it may be helpful to understand the answer.
Now, a co-vertex is the intersection point between an ellipse and its minor axis. On the graph of the ellipse, the [tex]b[/tex] is the distance from the center to where the ellipse intersects its minor axis, so our answer is A.
If a graphical representation would be helpful, I would take a look at the Math Warehouse article on the Equation of an Ellipse in Standard Form.
