Identify the aquatic mammal(s) from the following
(i) Balaenoptera
(ii) Equus
(iii) Delphinus
(iv) Pteropus
(v) Felis

Options

A. a) (i) and (iii)
B. b) (ii) and (iv)
C. c) (v) only
D. d) (iv) and (v)

Explanation

To identify the aquatic mammals from the given list, we will analyze each option based on their habitats.

### Step-by-Step Solution:

1. **Identify the first animal: Balaenoptera**
- Balaenoptera is commonly known as a whale. Whales are marine mammals that live in aquatic environments.
- **Conclusion**: Balaenoptera is an aquatic mammal.

2. **Identify the second animal: Equus**
- Equus refers to horses. Horses are terrestrial mammals that live on land.
- **Conclusion**: Equus is not an aquatic mammal.

3. **Identify the third animal: Delphinus**
- Delphinus is commonly known as a dolphin. Dolphins are also marine mammals that inhabit aquatic environments.
- **Conclusion**: Delphinus is an aquatic mammal.

4. **Identify the fourth animal: Pteropus**
- Pteropus is known as the flying fox or fruit bat. These are flying mammals that primarily inhabit terrestrial environments.
- **Conclusion**: Pteropus is not an aquatic mammal.

5. **Identify the fifth animal: Felis**
- Felis refers to cats. Cats are terrestrial mammals that live on land.
- **Conclusion**: Felis is not an aquatic mammal.

### Summary of Findings:
- Aquatic mammals identified:
- **Balaenoptera (whale)**
- **Delphinus (dolphin)**

### Final Answer:
The aquatic mammals from the given options are **(i) Balaenoptera and (iii) Delphinus**.