To solve the question, we need to identify the tropospheric concentrations of NO, NO2, and O3 as represented in the graph by lines A, B, and C.
- Understanding the graph: The graph shows the variation in concentration of three atmospheric components over time (measured in hours). The concentration is displayed in ppm (parts per million).
- Analysis of the components:
- Line A: Typically, the concentration of NO peaks in the early morning and diminishes throughout the day. From the graph, Line A shows a pattern where it starts high at sunrise and decreases as the day progresses, consistent with typical NO behavior.
- Line B: NO2 concentrations generally increase during daylight due to photochemical reactions involving NO and ozone. Line B shows a pattern of increase during the day, which is characteristic of NO2.
- Line C: O3 concentration tends to rise during the day due to sunlight-driven reactions and peaks in the afternoon. Line C shows a rise in concentration during the day, peaking in the afternoon.
- Conclusion: Based on the expected behavior of these components, the correct representation is:
Therefore, the correct answer is: $\text{NO}, \text{NO}_2, \text{O}_3$.