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

Choices:  
A: A line roughly parallel to and south of the border between the US and Canada  
B: A line roughly parallel to and west of the US Atlantic coastline  
C: A line roughly parallel to and north of the border between the US and Mexico  
D: A line roughly parallel to and east of the US Pacific coastline    

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

Correct answer: A — A line roughly parallel to and south of the border between the US and Canada.

Why this is correct:
- The FCC defines “Line A” (47 CFR §97.3) as a set of coordinates forming a line that runs roughly parallel to, and south of, the US–Canada border from Washington to Maine.
- It exists to trigger coordination/protection requirements for certain services, which can affect Amateur operation in the 70 cm band ($420\text{–}450\ \mathrm{MHz}$) near the Canadian border.

Why the other choices are incorrect:
- B (west of the US Atlantic coastline): No FCC “Line” is defined along the Atlantic coast; this is a distractor.
- C (north of the US–Mexico border): “Line A” pertains to the northern (Canada) border, not the southern border.
- D (east of the US Pacific coastline): No FCC “Line” is defined along the Pacific coast; another distractor.

Useful rules of thumb:
- Remember “Line A” = “Along (the) Canada border” — think “A for Canada.”  
- If you are near the Canadian border (north of Line A area), always check additional restrictions/coordination notes for the $420\text{–}430$ and $440\text{–}450\ \mathrm{MHz}$ segments in Part 97 before operating.