Assertion : A reference frame attached to earth is an inertial frame of reference.
Reason : The reference frame which has zero acceleration is called a non inertial frame of reference.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false
D. If the assertion and reason both are false.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

**Assertion:** A reference frame attached to Earth is an inertial frame of reference.
**Reason:** The reference frame which has zero acceleration is called a non-inertial frame of reference.

### Step-by-step Solution:

1. **Understanding Inertial and Non-Inertial Frames:**
- An **inertial frame of reference** is one in which Newton's first law holds true. This means that an object at rest stays at rest, and an object in motion continues in motion with a constant velocity unless acted upon by a net external force. In such frames, the net force acting on an object is zero, leading to zero acceleration.
- A **non-inertial frame of reference** is one that is accelerating. In these frames, fictitious forces (like centrifugal force) appear to act on objects due to the acceleration of the frame itself.

2. **Analyzing the Assertion:**
- The assertion states that a reference frame attached to Earth is an inertial frame. However, Earth is not a perfect inertial frame because it rotates on its axis and revolves around the Sun. This means that there are forces acting on objects due to these motions, which implies that the frame attached to Earth experiences acceleration. Therefore, the assertion is **false**.

3. **Analyzing the Reason:**
- The reason states that a reference frame which has zero acceleration is called a non-inertial frame of reference. This is incorrect. A frame with zero acceleration is actually an inertial frame of reference. Therefore, the reason provided is also **false**.

4. **Conclusion:**
- Both the assertion and the reason are false. Thus, the correct answer is that both the assertion and the reason are incorrect.

### Final Answer:
Both the assertion and the reason are false.

---