She was just too busy yesterday, ( ) she would surely have gon

She was just too busy yesterday, ( ) she would surely have gone there with you.
A、however
B、for
C、therefore
D、otherwise
【正确答案】：D
【题目解析】：考核关联词语含义，however “但是”；for “原因”；therefore “因此”；otherwise “否则”。句子含义：她昨天太忙，否则她一定会和你一起去的。