Read the given statements carefully.
P: I am the most common fire extinguisher but not suitable for oil, petrol and electrical fires. I am heavier than oil and also, conduct electricity
Q : I am an excellent fire extinguisher and most suitable for oil, petrol and electrical fires. I also, form a blanket around the fire and bring down the temperature of the fuel.
Identify P and Q.

Options

A. `P-CO_2, Q-H_2O`
B. `P-H_2O , Q-CO`
C. `P-O_2 , Q-CO_2`
D. `P-H_2O , Q-CO_2`

Explanation

To identify P and Q from the given statements, we can analyze the characteristics described in each statement.

### Step-by-Step Solution:

1. **Analyze Statement P:**
- P states: "I am the most common fire extinguisher but not suitable for oil, petrol, and electrical fires. I am heavier than oil and also conduct electricity."
- From this description, we can deduce that P is referring to **water (H2O)**. Water is commonly used to extinguish fires caused by materials like wood and paper. However, it is not suitable for extinguishing fires involving oil, petrol, or electrical equipment due to its properties of being heavier than oil (which causes it to sink) and being a good conductor of electricity (which poses a risk of electric shock).

2. **Analyze Statement Q:**
- Q states: "I am an excellent fire extinguisher and most suitable for oil, petrol, and electrical fires. I also form a blanket around the fire and bring down the temperature of the fuel."
- This description matches **carbon dioxide (CO2)**. Carbon dioxide is effective in extinguishing fires involving oil and electrical equipment because it does not conduct electricity and it displaces oxygen, effectively suffocating the fire. It also forms a blanket over the fire, which helps in reducing the temperature.

3. **Conclusion:**
- Based on the analysis, we can conclude:
- **P = Water (H2O)**
- **Q = Carbon Dioxide (CO2)**

### Final Answer:
- P is Water (H2O)
- Q is Carbon Dioxide (CO2)