A genus with a single species is
A. Monotypic
B. Typical
C. Atypical
D. Polytypic

Hint: Monotypic genus in which one species comprises the genus and kind of special case in which a single species is described simultaneously. In the monotypic genus Eucharia, the madrone butterfly is the only present species in it. The ranking between the species and family such as genus is the biological classification that consists of the phylogenetically related and single isolated species in the monotypic genus.

Complete step by step answer: The species are infraspecific taxa, smaller and do not include the subspecies called a monotypic species. Unspecific and monospecific terms are preferred sometimes in the case of genera. In the special case in which the genus and single species are simultaneously described by the botanical nomenclature. Very few are subordinate taxa in the contrast of an oligotrophic taxon that contains more than one as compared to the other taxa. The contained taxon was monotypic within the higher-level taxon that was used as the term of monotypic taxon found only with the one subdivision. In the Tubulidentata, the aardvark is the only single species present. Amborella is the only one genus found in the order of amborellales and also called the name as Amborella trichopoda. The only one species, Cephalotus follicularis name of the Albany pitcher
plant present in the cephalotaceae family including with the one genus name as cephalotus.
Therefore the correct option is (A).

Note: In which the species have fewer numbers of organisms that are found in the genus that consist of a large number of the organisms. Donkey, Zebra, and horses are the given examples that belong to the same genus. But no species can have the same scientific name because the given scientific name for the species is unique and the genus is the more inclusive group of the organism.