we have

this is the equation of a vertical parabola open upward
Convert into vertex form




The vertex is the point
----> is a minimum
The range of the function is the interval--------> [-8,∞)
that means------> all real numbers greater than or equal to 
The domain of the function is the interval-----> (-∞,∞)
that means------> all real numbers
therefore
<u>the answer is the option</u>
All real numbers
see the attached figure to better understand the problem