Which group is defined as a collection of related organisms that can produce viable offspring?

The correct choice is the group defined as a collection of related organisms that can produce viable offspring, known as a species. In biological terms, a species is the basic unit of classification and represents a group of organisms that share common characteristics and can interbreed to produce fertile offspring. For example, all dogs belong to the same species and can breed to have pups that can grow into viable adult dogs.

Understanding the definition of a species is crucial because it emphasizes reproductive isolation; members of different species cannot produce offspring that are fertile. This aspect is a key component of the Biological Species Concept, which focuses on reproductive potential as the primary criterion for defining species.

Other groups in taxonomy, such as family and genus, consist of broader classifications that include multiple species or related organisms, and a population refers to individuals of the same species living in a specific area at a given time.