The correct answer is B) The longitude is 13°25'. The signal "G1325" is a format used to indicate a geographic position, where the "G" represents Greenwich and the numbers that follow represent the longitude in degrees and minutes. In this case, "1325" corresponds to 13 degrees and 25 minutes of longitude, which is the correct interpretation. The other options are incorrect because they do not accurately represent the meaning of the "G1325" signal. Option A refers to Greenwich Mean Time, option C refers to latitude, and option D refers to a zone time, none of which are the correct interpretation of the given signal.