Which of the following tips may be helpful in maintaining a good friendship?

A、“Afriendinneedisafriendindeed.”Nomatterwhatdifficultiesyouencounter,youcanalwaysdependonyourfriendtohelpyou.
B、Nomatterwhatourfriendasksustodo,weshouldnothesitatetodoit.
C、Becauseofthetightscheduleyoumayhave,it’snotadvisablethatyoushouldsetasidesometimeforyourfriends..
D、Weshouldbegratefultowhatfriendshavedoneforus.