we have

we know that
The equation of a vertical parabola into vertex form is equal to

where
(h,k) is the vertex of the parabola
if
----> the parabola open upward (vertex is a minimum)
if
----> the parabola open downward (vertex is a maximum)
In this problem convert the quadratic equation into vertex form
so


Group terms that contain the same variable, and move the constant to the opposite side of the equation

Complete the square. Remember to balance the equation by adding the same constants to each side


Rewrite as perfect squares


This is a vertical parabola open down (vertex is a maximum)
the vertex is the point

The range is the interval--------> (-∞,4]

All real numbers less than or equal to

therefore
the answer is the option
All real numbers less than or equal to
