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。