The main plant body is not differentiated into true root, stem and leaves in

The correct option is D bryophytes
In bryophytes, the plant body is thallus-like, prostrate or erect and attached to the substratum by unicellular or multicellular rhizoids. They lack true roots, stem or leaves but may possess root-like, leaf-like or stem-like structures. Whereas, the main plant body is differentiated into true root, stem and leaves in pteridophytes, gymnosperm and angiosperm.