- A Chordata
- B the phylum Annelida
- C only Echinodermata
- D a group Arthropoda
Correct answer: A. Chordata
Explanation: Presence of a notochord defines phylum Chordata.
Concept context
Phylum-level classification of the animal kingdom from Porifera to Chordata, based on body symmetry, coelom, and segmentation. One of the most example-heavy chapters for NEET.