*Question E1F04:
[97.3] Which of the following geographic descriptions approximately describes "Line A"?*  

*Correct Answer is  A: A line roughly parallel to and south of the border between the US and Canada*  

### AI Response: (may contain errors)  

The question asks about a geographic description of "Line A," which is related to the allocation of amateur radio frequencies in the United States. 

### Correct Answer: 
**A: A line roughly parallel to and south of the border between the US and Canada**

- This line is significant because it represents the boundary for certain amateur radio frequency allocations. Frequencies are often divided based on geographic regions, and this line helps define the areas where different rules and regulations apply.

### Why the Other Choices are Incorrect:
- **B: A line roughly parallel to and west of the US Atlantic coastline**
  - This choice is incorrect because it does not correspond to any significant boundary for amateur radio frequency allocations. The Atlantic coastline does not define a major division in the same way as the US-Canada border.

- **C: A line roughly parallel to and north of the border between the US and Mexico**
  - This choice is also incorrect. The US-Mexico border does not serve as a primary reference for amateur radio frequency allocations. Instead, it is the US-Canada border that is more relevant for these purposes.

- **D: A line roughly parallel to and east of the US Pacific coastline**
  - This choice is incorrect as well. Similar to choice B, the Pacific coastline does not define a significant boundary for amateur radio frequency allocations. The focus is on the northern border with Canada.

### Summary:
- The correct answer is based on the established geographic boundaries that influence amateur radio regulations. Understanding these boundaries is crucial for exam preparation, as they can affect frequency usage and licensing.

### Useful Rule of Thumb:
- Remember that geographic lines relevant to amateur radio often relate to international borders, particularly the US-Canada border for frequency allocations. Familiarize yourself with these key boundaries to help with similar questions on the exam.