What would be the meaning of the flashing light signal "D0910"?

The flashing light signal "D0910" is indeed intended to convey a specific message related to a date. In this format, the letter "D" represents the month of October, which is the fourth month in the standard maritime communication codes. The numbers following the "D," specifically "0910," indicate the numeric date and time associated with it.

Breaking it down further, "09" corresponds to the 9th day, and "10" represents the hour (10 o'clock). Therefore, the full signal indicates the date of October 9 at 10 o'clock, confirming that the answer is indeed B.

Understanding the significance of the various letters and numbers in flashing light signals is crucial for effective maritime communication, especially in emergencies where precise information delivery is vital.