Mashaal Masha
$$f(x)=(x-10)(x+13)$$

The function $f$ is defined by the given equation. For what value of $x$ does $f(x)$ reach its minimum?
Difficulty: Hard
A: 

$-130$

B: 

$-13$

C: 

$-\frac{23}{2}$

D: 

$-\frac{3}{2}$