Final answer:
The sister group to animals is the Opisthokonta, which is part of the domain Eukarya. In the options provided, this is correctly referred to as unikonts. The correct option is b.
Step-by-step explanation:
The sister group to animals in the context of Eukaryotic taxonomy belongs to the group known as Opisthokonta. This group is part of the larger classification within the domain Eukarya.
The key distinction for the question here is identifying the correct group among the options provided. The correct choice is unikonts, which is synonymous with the group Opisthokonta and includes both the animal kingdom and fungi.
Opisthokonta is one of the six supergroups within the domain Eukarya. The euglenoids or Euglenids, under the Excavata supergroup, are not the closest relatives to animals even though Euglena may exhibit some animal-like characteristics such as mobility.
The domain Eukarya is characterized by cells with membrane-bound nuclei and a diversity that includes unicellular organisms and complex multicellular life forms such as plants, animals, and fungi. Option b. is the correct one.