Systematic botany refers to the
A. System analysis
B. Systematic arrangement of organs of plants
C. Systematic study of organelles and tissues
D. Methodical study of plants, dealing with identification nomenclature and classification

Hint:Systematic botany involves the description and denomination of plants. This is done by considering the structure of plants, functions of plants, and the classification of plants. Systematic botany can also be defined as the science of plant diversity.

Complete answer:Two related fields of biology named taxonomy and systematics deal with the classification and diversification of species respectively. Systematics is the biology study of the diversification of species based on their structure, function, etc. Systematics governs the evolutionary history along with the phylogenetic relationship. Systematic involves the addition of taxonomy and phylogeny. Systematic botany particularly applies all of its concepts to plant species.
Classification of species is essential as there is a vast diversity of organisms. Classification allows the organization of species into manageable categories. Classification allows easy identification of species. Systematic botany does classification based on the structure of plants. The main parts of plants are stems, roots, and leaves. But each of the plant species has a unique distribution of these parts which allows them to be differentiated from one other. Every plant part serves a different function in different plants and this makes the basis for differentiation in them. The most accepted classification of plants includes monocotyledons, dicotyledons, gymnosperms, and angiosperms. Systematic botany not only classifies plant species but also relates them to the phylogenetic tree of evolution.

So, option D is the right answer.

Note: Biosystematics delimits naturally occurring plant species that make the biotic community. The evolution of a group of taxa is established using systematic botany by understanding the phylogenetic and evolutionary trends. Biosystematics also helps in gathering data based on modern concepts in addition to morphology and anatomy.