Given:
The equation of the function is

We need to determine the vertex form.
Vertex form:
The vertex form of the equation of the parabola can be determined by solving the function
using completing the square method.
The vertex form of the function is of the form

We need to write the vertex form of the function in the form of

Hence, let us solve the function
using completing the square method.
Thus, we have;


Thus, the vertex form of the function is

Hence, Option A is the correct answer.