Main causes of acid rain is

Options

A. presence of nitric acid
B. presence of chloric acid
C. presence of sulphuric acid.
D. Both (1) and (3)

Explanation

### Step-by-Step Solution:

1. **Understanding Acid Rain**: Acid rain refers to any form of precipitation (rain, snow, sleet, or hail) that has a higher acidity than normal. This increased acidity is primarily due to the presence of certain acids in the atmosphere.

2. **Identifying the Main Acids**: The two main acids that contribute to acid rain are:
- Nitric Acid (HNO3)
- Sulfuric Acid (H2SO4)

3. **Analyzing the Options**:
- **Option A**: Presence of Nitric Acid (HNO3) - This is correct as nitric acid is a significant contributor to acid rain.
- **Option B**: Presence of Chloric Acid (HClO3) - This is incorrect as chloric acid is not a major contributor to acid rain.
- **Option C**: Presence of Sulfuric Acid (H2SO4) - This is also correct as sulfuric acid is another major contributor to acid rain.
- **Option D**: Both first and third - This option combines the correct acids (nitric and sulfuric) and is therefore the correct answer.

4. **Conclusion**: The main causes of acid rain are the presence of nitric acid and sulfuric acid. Therefore, the correct answer is **Option D: Both first and third**.