The right answer is A) Class.
We can see in the table that the human and the tiger are from the same class. (Mammalia).
Mammals (Mammalia) are a taxon and a clade (a cladistic grouping of biological lines) of vertebrate animals. Their range is global, they have conquered a large part of the ecological niches of the macrofauna and remain one of the dominant taxa since the Eocene.
The key feature of this clade (from which its name comes from) is the breastfeeding of young from a specialized skin and glandular secretion called milk. Newborns systematically require parental care because of their immature digestive system at birth (milk is their vital and obligatory source of food). Other key features distinguish mammals from other taxa, including fossils.