Why do we know that the fault is younger than the three rock layers

The principle of cross-cutting relationships states that a fault or intrusion is younger than the rocks that it cuts through.

Explanation:

The fault cuts through all three sedimentary rock layers

So the fault must be the youngest feature.

It's the closest

Explanation:

I'm not sure but I think its correct :) hope this helps

true, i don't really know what you're asking but from the info you provided im guessing the answer is true.