Final answer:
Precipitation reactions occur when cations and anions combine to form an insoluble ionic solid. The formation of a precipitate depends on the solubility rules for common ionic solids.
Step-by-step explanation:
Precipitation reactions occur when cations and anions in aqueous solution combine to form an insoluble ionic solid called a precipitate. The formation of a precipitate depends on the solubility rules for common ionic solids. By consulting these rules, one can determine whether a precipitate will form when A and B are mixed. Therefore, the answer to the question depends on the specific substances A and B, making option c) the correct answer.