Explanation:

The Earth's atmosphere is primarily composed of nitrogen ($\text{N}_2$) at about $78\%$, oxygen ($\text{O}_2$) at about $21\%$, and argon ($\text{Ar}$) at about $0.93\%$. Carbon dioxide ($\text{CO}_2$) is a trace gas, but it is a very important greenhouse gas. Its concentration has been increasing due to human activities, but it remains a small percentage of the total atmospheric volume. Option (A) is correct because the approximate percentage of carbon dioxide in the atmosphere is around $0.03\%$ to $0.04\%$. Specifically, in recent years, it has risen to approximately $0.041\%$ or $410$ parts per million (ppm). Options (B), (C), and (D) are incorrect as $0.3\%$, $1\%$, and $2.3\%$ are significantly higher than the actual concentration of $\text{CO}_2$ in the atmosphere.