Poultry is the class of domesticated fowl used for food or for their eggs. The correct answer is option 'C', which includes Chicken, Ducks, Turkey, and Geese.

Explanation:
Poultry refers to domesticated birds that are primarily raised for their meat or eggs. These birds are commonly found on farms and are a major source of food for humans. Let's take a closer look at each option to understand why option 'C' is the correct answer.

Option 'A': Penguins, Sparrows, Chicken, Peahens
- Penguins: Penguins are flightless birds that are not typically raised for food or egg production. They primarily inhabit the Southern Hemisphere and are known for their unique characteristics, such as their ability to swim and dive.
- Sparrows: Sparrows are small birds that are not commonly raised for food or eggs. They are often found in urban areas and are known for their lively chirping.
- Chicken: Chickens are one of the most common types of poultry. They are domesticated birds that are raised for their meat and eggs. Chicken is a popular source of protein and is consumed worldwide.
- Peahens: Peahens are female peafowls, also known as peacocks. While they are not typically raised for food, they are often kept for their ornamental value due to their beautiful feathers.

Option 'B': Turkey, Chicken, Peahens, Falcons
- Turkey: Turkeys are large birds that are commonly raised for their meat, especially during festive occasions such as Thanksgiving. They are native to North America and have become popular worldwide.
- Chicken: As mentioned earlier, chickens are a common type of poultry that are raised for meat and eggs.
- Peahens: Peahens are female peafowls and are not typically raised for food.
- Falcons: Falcons are birds of prey and are not commonly used for food production. They are known for their hunting abilities and are often trained for falconry.

Option 'C': Chicken, Ducks, Turkey, Geese
- Chicken: As mentioned earlier, chickens are a common type of poultry that are raised for meat and eggs.
- Ducks: Ducks are also a type of poultry that are raised for their meat and eggs. They are known for their aquatic habits and are often found near water bodies.
- Turkey: Turkeys, as mentioned earlier, are commonly raised for their meat.
- Geese: Geese are large water birds that are also raised for their meat and eggs. They are known for their honking sound and are commonly found in both domestic and wild settings.

Option 'D': Penguins, Geese, Ducks, Chicken
- Penguins, as mentioned earlier, are not typically raised for food.
- Geese and ducks are both types of waterfowl that are raised for their meat and eggs.
- Chicken, as mentioned earlier, is a common type of poultry.

By analyzing each option, we can conclude that option 'C' (Chicken, Ducks, Turkey, Geese) is the correct answer as it includes four birds that are commonly raised for food and egg production.