正确答案
试题解析
解析:问题中的关键词是eight。利用问题句中的特征词32 categories,eight,Irish(爱尔兰的)dolphins共同作为答案线索,对应原文第三第二句,Of the categories,he found most were used by both sets of dolphins—but eight were only heard from the Irish dolphins.从句中可以知道答案相关句与问题句的句意一致:32种啸声中有8种是爱尔兰海豚独有的,所以答案是A。