Which Annex of MARPOL requires ships to possess an International Air Pollution Prevention (IAPP) certificate?

The correct choice is determined by understanding the purpose and regulations outlined in each annex of the MARPOL convention. Annex VI of MARPOL specifically addresses the prevention of air pollution from ships. It sets limits on sulfur oxides (SOx) and nitrogen oxides (NOx) emissions from ship engines, as well as controls for ozone-depleting substances. To ensure compliance with these environmental standards, ships are required to possess an International Air Pollution Prevention (IAPP) certificate, which serves as proof that the vessel has been constructed and equipped to meet these stringent regulations.

In contrast, other annexes focus on different aspects of marine pollution. Annex I deals with the prevention of pollution by oil, Annex II regulates the control of pollution by noxious liquid substances in bulk, and Annex V addresses the disposal of garbage from ships. None of these require the IAPP certificate, as they pertain to different pollutants and regulatory measures. Hence, the requirement for an IAPP certificate is unique to Annex VI, making it the correct answer.