The correct answer is D) moderate. According to the International Code of Signals, a swell of 8-10 feet in height and from the northeast would be considered "moderate." This is because the Code defines a moderate swell as having a wave height between 6-12 feet. The direction of the swell from the northeast is also relevant information that helps classify it as moderate. The other options are incorrect because "high" (A) would refer to a swell greater than 12 feet, "rough" (B) would describe a swell with irregular, tumbling waves, and "confused" (C) would indicate a swell with no dominant direction. The given swell characteristics fit best with the "moderate" classification.