Consider following features.

(A) Organ system level of organisation

(B) Bilateral symmetry

(C) True coelomates with segmentation of body 

Select the correct option of animal groups which possess all the above characteristics

All the phyla mentioned in the options (Annelida, Arthropoda, Mollusca and Chordata) are bilaterally symmetrical true coelomate animals with organ-system level of organisation. But metamerism (segmentation) is found only in Annelida, Arthropoda and Chordata. Molluscs are unsegmented. Metamerism refers to the division of the body into segments with a serial repetition of at least some organs. Metamerism allows fl exibility and adaptability in an organism’s body plan, as the segments can be modifi ed or specialised for different functions, depending on the needs of the organism. 

(1), (3) and (4) are incorrect since mollusks are unsegmented.