Question

求助英语完形最后一空为什么选A不选B

At the age of 31, Dad married my mother who was a school teacher. In the following spring I came 6 into the world. Life became hard, so my mother felt unsatisfied. She told Dad that they must make a 7 .
My mother had 8 of how some famous persons, especially Thomas Edison who was born in a poor family, fought against fate and achieved greatness and fame. And she 9 that I would some day become a great leader，ruling men or cities and Dad should be a successful businessman. So she persuaded Dad to give up his job as a farmhand, sell his horse and 10 a small business of his own. And I went to high school and college. She even sent me abroad for 11 education when I graduated from college. Under the drive of my mother’s hope, Dad and I 12 what we have today. Dad runs a big international 13 and I am a successful lawyer enjoying great fame in my country, 14 not a leader as my mother expected.
Dad said, without my mother, we wouldn’t be what we are today; at least, he would remain a farmhand. 15 he got a lesson of life —sometimes we really need drive from outside.
15 A．So B．However C．Or D．Because

Answer 1

父亲说，没有我妈妈，我们就不会有今天。至少，（没有妈妈的帮助）他目前还会是一名农民。
（15 所以）他从生命中学到了一课---有时候我们真的需要外力的推助（才能活得更好）。

So （所以）承接上文，表示有因有果。however 的话逻辑反了