Final answer:
The correct option is D). The two lineages of the phylum Platyhelminthes are the Catenulida and the Rhabditophora, representing a basic division between typically non-parasitic and parasitic or free-living species within the flatworms.
Step-by-step explanation:
The two lineages of the phylum Platyhelminthes are the Catenulida and the Rhabditophora. The Catenulida, also known as 'chain worms', consist of just over 100 species that typically reproduce asexually by budding. The Rhabditophora are 'rhabdite bearers' and include both free-living flatworms, which use mucus for mobility and defense, and parasitic species like trematodes and cestodes, which are significant as human parasites. These two groups represent the fundamental distinction within the flatworms, separating typically non-parasitic chain worms from a diverse clade that includes many parasitic and free-living species.