Premise: "A surfer has just fallen off his surfboard and only his feet are visible above the water."\nHypothesis: "The surfer fell after the wave hit hijm."\nDo we know that the hypothesis entailed by the premise?
Step-by-step reasoning:
it is not possible to tell
Just because he fell off doesn't mean that he fell off after the wave hit him.

.

So, the final answer is it is not possible to tell