TOEFL Listening: TPO-TOEFL阅读TPO - K6ZG8TODW9W73381N$

Why does the author mention that "The green ice portion was textured by seawater erosion"? A. To explain why cracks in the iceberg appeared light green instead of dark green B. To suggest that green ice is more easily eroded by seawater than white ice is C. To support the idea that the green ice had been the bottom layer before capsizing D. To explain how the air bubbles had been removed from the green ice