The correct option is B Protista
Slime molds are saprophytic protists. Slime molds are also called myxomycetes and are not a plant or animal. It is not a fungus, though it sometimes resembles one. In Whittaker’s Five Kingdom Classification slime molds were placed under the Kingdom Protista because they share some common characteristics with the other organisms which belong to this kingdom. For example: Slime molds are eukaryotes, cell wall as well as nuclear membrane is present, the body organization is cellular and they show heterotrophic mode of nutrition.