The correct option is A Protista
In 1866, Ernst Haeckel proposed the three kingdom classification. He had divided the living organisms into three kingdoms namely:
Animalia - It includes all the animals that are present on the earth.
Plantae - It includes all the plant species.
Protista - It includes all the microorganisms, i.e.; fungi, bacteria etc.
Kingdom Protista is proposed by Ernst Haeckel.