Ans.
A phylogenetic tree shows a diagram of tree that describes evolutionary relationships between various biological species, on the basis of difference and similarities in their genetic and physical features.
According to this, the organisms of phylum echinodermata are most closely related to organisms with phylum chordata because both the phyla have organisms with a blastopore (develops into anus) and indeterminate cleavage, grow radially, and are deuterostomes.
Thus, the correct answer is option). 'echinodermata.'