Gemmae are multicellular green structures for vegetative propagation. These are found inside gemma cups in _________________.

In Marchantia, the plant body consists of a dorsoventrally flattened, prostrate and dichotomously branched thallus. The thalli are conspicuous, the apex of each thallus is notched. Along the mid-rib are present characteristic, prominent goblet or cup-shaped structures, the gemma cups, with smooth, dentate or frilled margins. These cups enclose asexual reproductive bodies called gemma.So the correct option is B.