Assertion : Zn, Cd and Hg are not regarded as transition elements.
Reason : The electronic configurations of Zn, Cd and Hg are represented by the general formula`(n-1)d^10ns^2`.

Options

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

Answer

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

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that Zn (Zinc), Cd (Cadmium), and Hg (Mercury) are not regarded as transition elements.
- This is true because transition elements are typically defined as elements that have an incomplete d-subshell in one or more of their oxidation states.

2. **Understanding the Reason**:
- The reason given is that the electronic configurations of Zn, Cd, and Hg can be represented by the general formula (n-1)d^10 ns^2.
- The electronic configurations for these elements are indeed:
- Zn: [Ar] 3d^10 4s^2
- Cd: [Kr] 4d^10 5s^2
- Hg: [Xe] 4f^14 5d^10 6s^2
- In all these cases, the d-orbitals are completely filled (d^10), which means they do not have any unpaired electrons.

3. **Transition Elements Definition**:
- Transition elements are characterized by having partially filled d-orbitals. Since Zn, Cd, and Hg have fully filled d-orbitals, they do not meet this criterion.

4. **Conclusion**:
- Both the assertion and the reason are true. The reason correctly explains why Zn, Cd, and Hg are not considered transition elements, as their d-orbitals are fully filled.

### Final Answer:
- Both assertion and reason are true, and the reason is the correct explanation of the assertion. Therefore, the answer is **Option 1**.