Answer
d
Work Step by Step
Forces $\overrightarrow{F}_1$ and $\overrightarrow{F}_3$ are in opposite directions, so their vectors cancel, leaving the larger force, $\overrightarrow{F}_3$ with some force remaining. Adding $\overrightarrow{F}_2$ to the leftover $\overrightarrow{F}_3$ results in a combined force between that pointing down and to the left. This direction is mostly closely shown in answer d.
