I'm terribley sorry,____ I can't go hiking with you this Saturday.It's ok!We can go together next time.A so B but C and D or 应该选 B 还是C 有点纠结~

I'm terribley sorry,____ I can't go hiking with you this Saturday.It's ok!We can go together next time.A so B but C and D or 应该选 B 还是C 有点纠结~
I'm terribley sorry,____ I can't go hiking with you this Saturday.
It's ok!We can go together next time.
A so B but C and D or
应该选 B 还是C 有点纠结~

I'm terribley sorry,____ I can't go hiking with you this Saturday.It's ok!We can go together next time.A so B but C and D or 应该选 B 还是C 有点纠结~
C
but表示转折,and表示链接上文,意思相近或者还没有说完的话.很明显上句已说“我非常抱歉……”若再用but,抱歉了语气再转折成什么了?怎么也说不通的,抱歉了用and接着说抱歉的内容