Assertion : Pyrrole is an aromatic heterocyclic compound
Reason : It lias cyclic delocalised `6 pi `electrons

Options

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

Answer

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

### Step-by-Step Solution:

1. **Understanding Pyrrole**:
Pyrrole is a five-membered ring compound that contains one nitrogen atom. The structure of pyrrole can be represented as follows:
```
H
\
C
/ \
C C
\ /
N
/ \
H C
```

2. **Checking Aromaticity**:
To determine if pyrrole is aromatic, we apply Huckel's rule, which states that a compound must meet the following criteria:
- It must be cyclic.
- It must be planar.
- It must be fully conjugated (p-orbitals must overlap).
- It must contain \(4n + 2\) π electrons, where \(n\) is a non-negative integer.

3. **Cyclic Structure**:
Pyrrole is indeed cyclic as it forms a closed loop with its five atoms.

4. **Planarity**:
Pyrrole is planar because all the atoms in the ring lie in the same plane, allowing for effective overlap of p-orbitals.

5. **Conjugation**:
The nitrogen atom in pyrrole has a lone pair of electrons that can participate in delocalization. This means that the electrons can move freely around the ring, contributing to the conjugation.

6. **Counting π Electrons**:
In pyrrole, the π electrons come from:
- The double bonds (2 double bonds contribute 4 π electrons).
- The lone pair on nitrogen contributes 2 π electrons.
Thus, the total number of π electrons is \(4 + 2 = 6\).

7. **Applying Huckel's Rule**:
To check if pyrrole satisfies Huckel's rule, we set \(4n + 2 = 6\):
\[ 4n + 2 = 6 \implies 4n = 4 \implies n = 1 \]
Since \(n\) is a non-negative integer, pyrrole is aromatic.

8. **Conclusion**:
Since both the assertion (Pyrrole is an aromatic heterocyclic compound) and the reason (It has cyclic delocalized 6 π electrons) are true, and the reason correctly explains the assertion, we conclude that the correct answer is:
- **Both assertion and reason are true, and the reason is the correct explanation of the assertion.**

### Final Answer:
The correct option is **A**.