The correct option is C X - Artificial, Y - Natural
Artificial system of classification classifies organisms on the basis of only one or a very few specially chosen morphological features. Early classification, Aristotle’s classification and Carl Linneaus’ classification are examples of artificial systems of classification.
Natural system of classification classifies organisms on the basis of not just external morphological features but also internal features. Bentham and Hooker’s classification system is an example of a natural system of classification. It considers the ultrastructure, anatomy, embryology and phytochemistry of the plants.