*Question E3C07:
Which of the following indicates the greatest solar flare intensity?*  

*Correct Answer is  D: Class X*  

### AI Response: (may contain errors)  

The correct answer to the question about solar flare intensity is Class X. Here's a breakdown of why this is the case and why the other options are incorrect:

### Explanation of the Correct Answer:
- **Class X**: This class indicates the most intense solar flares. The classification system for solar flares is based on their X-ray brightness, with Class X being the highest level. Flares in this class can cause significant disturbances in the Earth's ionosphere, affecting radio communications and satellite operations.

### Explanation of Incorrect Answers:
- **Class A**: This class represents the weakest solar flares. They have minimal impact on Earth and are generally not associated with significant radio disruptions.
  
- **Class B**: This class is slightly stronger than Class A but still relatively weak. Class B flares can cause minor effects on radio communications but are not as impactful as higher classes.
  
- **Class M**: This class indicates moderate solar flares. While they can cause some disruptions, they are not as intense as Class X flares. Class M flares can affect high-frequency radio communications but are less severe than Class X.

### Summary of Solar Flare Classes:
- **Class A**: Weakest
- **Class B**: Minor
- **Class M**: Moderate
- **Class X**: Strongest

### Rule of Thumb:
- The classification of solar flares is logarithmic, meaning that each class represents a tenfold increase in intensity. For example, a Class X flare is ten times more intense than a Class M flare.

This classification system helps amateur radio operators understand the potential impact of solar activity on radio communications and prepare accordingly.