Which of the following is not possible?

a. radially symmetrical diploblast

b. diploblastic eucoelomate
c. protostomic coelomate

d. bilaterally symmetrical deuterostome

Further subdivision of animals with three germ layers (triploblasts) results in the separation of animals that may develop an internal body cavity derived from mesoderm, called a coelom, and those that do not.

b. diploblastic eucoelomate : Eucoelomates are animals with a true coelom. The presence/absence of a coelom is a division of triploblasts only. Thus, a diploblast cannot be a eucoelomate.

a. radially symmetrical diploblast : All diploblasts are radially, biraldially or rotationally symmetrical.

c. protostomic coelomate : Protostomic coelomates include mollusks, annelids, arthropods, pogonophorans

d. bilaterally symmetrical deuterostome: Bilaterally symmetrical deuterostome include members of the phylum chordata.