The best and most correct answer among the choices provided by your question is the second choice or letter B. The taxon species may be defined by reproductive isolation and morphology.
In biology, a taxon (plural taxa; back-formation from taxonomy) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit.
I hope my answer has come to your help. Thank you for posting your question here in Brainly.
