Answer the following questions for the function $$f(x) = x \sqrt{x^2 + 6 x + 25} + 3 \sqrt{x^2 + 6 x + 25 }$$ defined on the interval $[ -10, 4 ]$. All answers refer to $x$-coordinates.

A. $f(x)$ is concave down on the region to
B. $f(x)$ is concave up on the region to
C. The inflection value for this function is
D. The minimum for this function occurs at
E. The maximum for this function occurs at