The best statement that describes the comparison between the international reactions to the Rwandan genocide and the 9/11 attacks is:
The international community immediately responded to 9/11 but did not react to Rwanda until after the genocide occurred, based largely on differences in geography, culture, and political systems.
This statement captures the key differences in the timing and nature of the international responses to both events. The 9/11 attacks received immediate global attention and led to a swift response, while the Rwandan genocide was largely overlooked by the international community until it was too late to prevent the mass killings.