题目解析:
EXCEPT 题,排除法,ACD 都定位到第三句话:These expeditions were likely driven by population growth and political dynamics on the home islands, as well as the challenge and excitement of exploring unknown waters. A 选项的 their number increased 对应原文第三句的 population growth;正确,不选;C 的 political situation at home 对应第三句中的 political dynamics on the home islands,正确,不选;D 选项的 challenging and exciting 对应第三句中的 challenge and excitement,正确,不选;B 没说,选。