The answer is the last option, ∠AFB
The first thing we must know to answer this question is what a vertical angle even is what a vertical angle even is. A vertical angle is a pair of opposite angles made by intersecting lines. Take an X for example. The two angles on each side are vertical angles and the two on the top and bottom are vertical angles. Vertical angles have the same angle degree and are congruent.
Below I attached a picture, where both of the A's are congruent vertical angles and both of the B's are congruent vertical angles to give you an idea of what to look for :)
Now that we know what we are looking for, we just pick out the three points that make up this angle that we are looking for. The angle that is opposite of ∠EFD is ∠AFB
And that's our answer! :)
Thank you for your question! I hope this helped! Have an amazing day and feel free to let me know if I can help you any further! :D