Choice A is a preposition that indicates going from one end to another. (I went through a tunnel.)
Choice C is a preposition used when one is passing something to reach another thing. (I went over the bridge.)
Choice D is a preposition used with times or specific venues. (I went at ten o'clock. We met at the mall.)
The correct answer is B. The preposition "on" is used with geographic places such as "island" or mountain.