**Explanation:**

The correct answer is option **D) Langur**. Langurs are known to make strong warning calls for animals from the dangers like tigers and leopards. Let's explore this in more detail:

**1. Langurs**:
- Langurs are a type of Old World monkey that are native to the Indian subcontinent.
- They are known for their distinctive black face with a white ruff of fur, and their long tails.
- Langurs are highly social animals that live in troops consisting of multiple males, females, and their offspring.
- They are arboreal, meaning they spend most of their time in trees, and are excellent climbers.

**2. Warning Calls**:
- Langurs have evolved a unique vocal communication system to warn their troop members of potential dangers.
- When they spot a predator like a tiger or leopard, langurs emit a series of loud and distinctive alarm calls.
- These calls serve as a warning to other langurs in the troop, signaling them to be on high alert and take evasive action.
- The warning calls of langurs are powerful and can be heard over long distances, alerting nearby animals of the potential threat.

**3. Reason for Langurs' Warning Calls**:
- Langurs make strong warning calls for animals like tigers and leopards because these predators pose a significant threat to their survival.
- Tigers and leopards are large carnivores that can prey on langurs, especially the young and vulnerable individuals.
- By emitting warning calls, langurs help to protect their troop members from potential attacks and increase their chances of survival.

**4. Importance of Warning Calls**:
- Warning calls play a crucial role in the survival of langurs and other animals living in similar habitats.
- By alerting each other to the presence of predators, langurs can take appropriate action, such as seeking safety in trees or moving away from the danger.
- Warning calls also benefit other animals in the vicinity, as they can take cues from the langurs' alarm calls and respond accordingly.

In conclusion, langurs are known to make strong warning calls for animals like tigers and leopards. These vocalizations serve as an important means of communication within their troop, helping to alert and protect each other from potential dangers.

Langur