时间状语从句的问题

半夏死磕GT

Less than 35 years after the release ofAfrican honeybees outside Sao Paulo, Brazil, their

descendants, popularly known as killerbees, had migrated as far north as southern Texas.

(A) Less than 35 years after the releaseof African honeybees outside Sao Paulo, Brazil,

(B) In less than 35 years since releasingAfrican honeybees outside Sao Paulo, Brazil,

(C) In less than the 35 years sinceAfrican honeybees had been released outside Sao Paulo,

Brazil,

(D) It took less than 35 years from therelease of African honeybees outside Sao Paulo, Brazil,

when

(E) It took less than the 35 years afterthe time that African honeybees were released outside

Sao Paulo, Brazil, and then  

答案是A；想问下，less than 35 years 前不用介词吗？for或者其他