——Dad,when will you be free?You agreed to go to the seaside

——Dad,when will you be free?You agreed to go to the seaside with me four days ago.
——Dad,when will you be free?You agreed to go to the seaside with me four days ago.
——I'm sorry,Jean.But me I think I will bave a ______holiday soon.
A.four-days B.four-day
C.four days D.four day
应该选什么?为什么?请指教!