The food is very good . . . . . . . . that restaurant. A. at B. of C. in D. with

The correct answer is A. at.

The preposition “at” is used to indicate a specific location. In this case, the speaker is referring to a specific restaurant, so the preposition “at” is the most appropriate choice.

The other options are not as accurate. The preposition “of” is used to indicate possession or association. In this case, the speaker is not saying that the food is owned by the restaurant, so the preposition “of” is not the best choice.

The preposition “in” is used to indicate a location within a larger area. In this case, the speaker is not saying that the food is located inside the restaurant, so the preposition “in” is not the best choice.

The preposition “with” is used to indicate a relationship or association. In this case, the speaker is not saying that the food is associated with the restaurant, so the preposition “with” is not the best choice.