The other responder used in. I hadn't thought of that. Common usage would probably use "in" but what I have pointed out as a use is also possible. The point is that whatever you use, it must be a preposition.
Explanation: By could also be used if there is an extensively long series of events before that “end” occurs. Other than that, “in” is most commonly written.
The only line which demonstrates a simile (a comparison using the words <em>like </em>or <em>as</em>) is B) It is in the small things we see it. The child's first step, as awesome as an earthquake.<em />
