The correct option is B Nostoc
Penicillium and Agaricus belong to kingdom Mycota or Fungi. Volvox is a colonial green alga. These organisms are eukaryotic and possess a nucleus with a well developed nuclear membrane and nuclear pores in that membrane. Nostoc is a prokaryotic organism belonging to kingdom Monera. It lacks a well-developed nucleus having a proper nuclear membrane and nuclear pores. Thus, the correct answer is option B.