Answer
$\bf{D}$
Work Step by Step
In order to match the differential equation with its graph, we need to look at the certain patterns using the differential equation.
Let us consider some cases:
1. When we consider $x=-y$, then the slope becomes null (zero); thus we eliminate the graphs A and C.
2. When we both consider $x$ and $y$ positive values then the slope also becomes positive); thus we eliminate the graph for B.
Hence, our correct graph is $\bf{D}$
