单选题 Yangtze River flows at a width of up to 2km and an average depth of between 6 and 15m through a large plain with many lakes. This area is______to severe flooding and accumulation of river sediment.
【正确答案】 C
【答案解析】解析：句子大意为：扬子江的最大宽度为2km，平均深度在6m至15m之间，流经大面积的平原和湖泊。所流经的区域易患严重洪灾和泥沙沉积。在给出的选项中：object“反对”；particular“特定的”；subject“易患于”；prone“倾向于”。所以，正确答案是C。