Answer:
A hand comes out of the lake to grab King Arthur’s sword.
Step-by-step explanation:
Supernatural events are things that do not happen regularly and that strecht immagination into beliving them, from the options the most supernatural things is that a hand would come out of the water to grab the sword, since there is no logical reason or possible way in which there´s a hand or someone below the water waiting for the sword to be handled.