The correct option is A Nomenclature of plants
The binomial system of nomenclature has been an important factor in the development of taxonomy. Before the middle of 18th century the names of plants were polynomials consisting of several words. The confusion arising due to this emphasised the need of a code of nomenclature by which the naming of plants might be regulated. Many codes have been proposed, buy only two have received the support of international conferences, the Paris Code of 1867 and the Vienna Code of 1905. These two codes have been a great help in stabilising nomenclature.