I promise my mother ican deal with my own things and i will

I promise my mother ican deal with my own things and i will be back for ____
I promise my mother I can deal with my own things and i will be back for _____ advice when I cannot.
A.a B.an C./ D.the
我知道是选C,但是有点想不通为什么advice前面不能加the,我觉得这里有指定的意思阿,求详解