To solve this question, the user needs to have knowledge of prepositions and their usage.

The blank space in the sentence requires a preposition that indicates the direction of the shop relative to the street.

Now, let's go through each option and explain why it is right or wrong:

A. "at": This preposition is not the best fit for the sentence because it doesn't clearly indicate the direction of the shop. It can be used to indicate a location, but the sentence requires a preposition that shows direction. Therefore, option A is incorrect.

B. "in": This preposition doesn't indicate the direction of the shop. It is used to indicate that something is inside a location or an object. Therefore, option B is incorrect.

C. "on": This preposition is commonly used to indicate the position of something on a surface. It can also be used to indicate a direction that is along a road or path. In this sentence, "on" is the most suitable preposition as it indicates the direction of the shop relative to the street. Therefore, option C is correct.

D. "over": This preposition means "above" or "higher than". It doesn't indicate the direction of the shop relative to the street. Therefore, option D is incorrect.

The Answer is: C.