______it is ______you obtain,you must tell your parents.

正确答案为A,表示无论你得到什么,都要告诉父母.Whatever做表语,that是定语从句先行词.

我坚持选D.

可能是D

Maybe choose A
I cannot sure
补充回答你的问题:
我个人认为哦......
you obtain的句子的宾语是whatever it is,
但是可能这个句子是同位语从句,所以引导句子的that不可以省略,so I choose A.

B.No matter what 才可以在句子中做主语，而Whatever不能，
句子的意思是：无论你得到什么，你都得告诉你的父母

选B.因为no matter what it is 是 you abtain 的宾语.即you abtain no matter what it is,you must tell your parents.此句中you abtain 是 no matter what it is 的定语，也是形式主语。
二楼不对。whatever 做句子主语。no matter what 作宾语。