题目解析:
counterparts: 作名词,意为对等物,相对物。B选项意为对等物,等量物,是考核词的近义词。Though the leading Mediterranean states were small in size, they were considerably wealthier than their northern counterparts.对应原文中呈现出了比较的逻辑,而比较的对象为 leading Mediterranean states和northern counterparts,结合上下文和这里的比较关系,就可以猜测counterparts的意思。A选项associates意为合伙人,伴侣;C选项意为对手;D选项意为崇拜者。只有B选项的equivalents代入,才可以使这个句子最为连贯,语境也说得通。C选项有一定迷惑性,代入也连贯。但是B选项和coutnerparts的意思最为接近。因此答案为B选项。