Sweet potato is homologous to Potato, Ginger, Turnip, Colocasia.

The correct option is D Turnip. A tuberous root or storage root, is a modified lateral root, enlarged to function as a storage organ. Examples of plants with tuberous roots include the sweet potato, cassava, and dahlia. Turnip has a napiform fleshy taproot. Taproots of turnip get swollen and store food. Both are modified roots. Thus, the correct answer is option D.