The correct answer is option 2: 2, 3, and 4 only.

To understand why this answer is correct, let`s dissect each option:

1. Freshwater: Corals require saltwater to survive and cannot tolerate freshwater. Therefore, freshwater is not needed for the growth of corals.

2. Clear shallow salt water: This is one of the essential factors for coral growth. Corals thrive in clear shallow saltwater environments where they can easily access nutrients and light.

3. Plenty of sunlight for photosynthesis: Sunlight is crucial for the growth of corals as they have a mutualistic relationship with photosynthetic algae called zooxanthellae. The algae provide food to the corals through photosynthesis, and in return, the corals give the algae a protected environment.

4. Warm water between 23°C and 25°C: Corals are sensitive to temperature changes, and they require warm water to grow. The optimal temperature range for most coral species is between 23°C and 25°C.

Therefore, the correct factors needed for the growth of corals are clear shallow salt water, plenty of sunlight for photosynthesis, and warm water between 23°C and 25°C.