# Minimum number of vectors needed in different planes for their resultant to be zero

I was doing some problems on physics when i saw a question that asked what is the minimum number of vectors needed in different planes for their resultant to be zero I thought about this and came to the conclusion that it should be three. ex : suppose one vector is $3\mathbf{\hat{i}}+ 3\mathbf{\hat{j}}$ in the $xy$ plane , another $-3\mathbf{\hat{i}} + 3\mathbf{\hat{k}}$ in the $xz$ plane and another $-3\mathbf{\hat{j}} -3\mathbf{\hat{k}}$ in the $yz$ plane .

So their resultants should be zero. But the answer is $4$. I don't understand why.

Please correct me if am making a mistake.