老PREP SC-3 逻辑主语 求助

0815030128

Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil, their descendants, popularly known as killer bees, had migrated as far north as southern Texas.

(A) Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil,
(B) In less than 35 years since releasing African honeybees outside Sao Paulo, Brazil,
(C) In less than the 35 years since African honeybees had been released outside Sao Paulo, Brazil,
(D) It took less than 35 years from the release of African honeybees outside Sao Paulo, Brazil, when
(E) It took less than the 35 years after the time that African honeybees were released outside Sao Paulo, Brazil, and then
答案A
分词短语在句首起状语作用，逻辑主语等于句子主语，可这里划线处主语不是 the release 吗？跟后面句子的主语明显不一致，怎么解？
求指点！谢谢大家~

sandychen168

逻辑主语是逗号后的their descendants