The best answer would be option 3:
Fault Q occurred before layer K was deposited.
If you'd like to know why:
As you can see in the diagram, fault Q does not cross layer K. It stops right under it, so this means that the fault occurred first, then over a span of time, layer K was deposited.
To rule out the rest:
The oldest layer is the one at the bottom so that should be Layer B.
The youngest should be the top-most layer, unless a fault or an intrusion cuts through it, so Layer K is the youngest.
The last option is wrong because fault Q cuts through all those layers, which means it happened after those layers were formed.
