Ans. (B). rodents and primates.
Given diagram represents a phylogenetic tree, which shows evolutionary relationships between organisms. The nodes in the tree denotes the ancestral lineage, while the tips of its branches denotes descendants evolved from that ancestor.
According to given tree, rodents and primates share most common recent ancestor as these branches are evolved from a common node and so, they are most closely related organisms.
Thus, the correct answer is options (B).
