How many characters does the short text messaging feature of the automatic identification system (AIS) allows for?

Correct Answer: Option D — 158 characters

AIS short safety-related messages are limited by the technical constraints of the VHF Data Link (VDL) slot structure. Per IMO and ITU-R M.1371 standards, these text messages are restricted to a maximum of 158 characters to ensure efficient transmission within the allocated time slots of the AIS system.