**Explanation:**

Fruits and leaves fall on the ground due to the force of gravity. Gravity is a force that pulls objects towards the center of the Earth. It is a fundamental force of nature and is responsible for various phenomena we observe in our daily lives, including the falling of objects.

**Gravity as the Correct Answer:**

The correct answer to the question is option 'B' - gravitational force. Here's a detailed explanation of why gravity is responsible for the falling of leaves and fruits:

1. **Force of Gravity:** The force of gravity is the attraction that exists between two objects with mass. In this case, the Earth and the leaves or fruits have mass, and therefore, they experience the force of gravity.

2. **Acceleration Due to Gravity:** When an object is near the surface of the Earth, it experiences an acceleration due to gravity. This acceleration is approximately 9.8 m/s^2 and is denoted by the symbol 'g'. This means that an object in freefall near the Earth's surface will accelerate at a rate of 9.8 m/s^2 towards the ground.

3. **Falling Objects:** When leaves or fruits detach from a tree or plant, they are no longer supported by any other force. Thus, they are subject to the force of gravity. Since gravity pulls objects towards the Earth, the leaves and fruits accelerate towards the ground due to the force of gravity.

4. **Path of Falling Objects:** The path followed by falling objects is a result of the combination of the initial velocity and the acceleration due to gravity. In the absence of any other forces, such as air resistance, falling objects will follow a straight-line path towards the Earth's surface.

5. **Effects of Air Resistance:** It is important to note that in reality, the motion of falling objects is influenced by air resistance. Air resistance is a force that opposes the motion of objects through the air. It can affect the speed and trajectory of falling objects, causing them to deviate from a straight-line path.

In conclusion, leaves and fruits fall on the ground due to the force of gravity, which is the attraction between objects with mass. The force of gravity causes the objects to accelerate towards the Earth's surface, resulting in their downward motion.