Concept:The correct preposition after the phrase “speak evil” is “of”.Explanation:We say “speak evil of someone” to mean saying bad or negative things about that person.Therefore, “speak evil of the dead” means “say bad things about those who have died”.The preposition “of” shows the connection between the action “speak” and the object “the dead”.The other options do not form the correct idiomatic expression.Thus, the sentence becomes: “Please, don’t speak evil of the dead.”Answer:B. of