Find Values Of $x$ And $y$ Such That Both $f_{x}(x, y)=0$ And $f_{y}(x, y)=0$

Multiple Choice

Find values of $x$ and $y$ such that both $f_{x}(x, y) =0$ and $f_{y}(x, y) =0$ .
- $f(x, y) =x+y+8 x y+3$

A) $\mathrm{x}=-\frac{1}{8}, \mathrm{y}=-\frac{1}{8}$
B) $\mathrm{x}=-\frac{1}{8}, \mathrm{y}=-\frac{3}{8}$
C) $\mathrm{x}=-\frac{3}{8}, \mathrm{y}=-\frac{1}{8}$
D) $\mathrm{x}=-\frac{3}{8}, \mathrm{y}=-\frac{3}{8}$