Identify the correct set of a genus of animals represent eutherians-

Options

A. Eryx, Balenoptera, Pan
B. Cavia, Felis, Pteropus
C. Macropus, Desmodus, Leo
D. Rhea, Elephas, Delphinus

Answer

To solve the question of identifying the correct set of a genus of animals that represent eutherians, we need to understand what eutherians are and analyze the options provided.

### Step-by-Step Solution:

1. **Understand Eutherians**: Eutherians, also known as placental mammals, are a group of mammals characterized by the presence of a placenta. This organ allows for a more extended gestation period and provides nutrients and oxygen to the developing embryo while removing waste products.

2. **Identify the Exclusions**: Eutherians exclude monotremes (egg-laying mammals like the platypus) and marsupials (mammals that carry and nurse their young in pouches, such as kangaroos).

3. **Analyze the Options**:
- **Option A**: Irix, Belenopetra, Pent - None of these are recognized genera of eutherians.
- **Option B**: Cavia, Felis, Pteropus - Cavia (guinea pigs), Felis (cats), and Pteropus (flying foxes) are all placental mammals.
- **Option C**: Macropus, Desmodus, Leo - Macropus (kangaroos) is a marsupial, and Desmodus (vampire bats) and Leo (lion) are not all eutherians.
- **Option D**: Rhea, Elephas, Delphinus - Rhea (a bird), Elephas (elephants, which are eutherians), and Delphinus (dolphins, which are also eutherians) but Rhea is not a mammal.

4. **Conclusion**: After analyzing the options, the correct set of genera that represent eutherians is **Option B: Cavia, Felis, Pteropus**.

### Final Answer:
**The correct set of a genus of animals representing eutherians is Option B: Cavia, Felis, Pteropus.**