Given S= [a,b,c,d] belongs to R4,anot = 0. Find a basis that is a subset of s.

I am unsure what theanot = 0 means.

Would it just be a(1,0,0,0)+b(0,1,0,0)+c(0,0,1,0)+d(0,0,0,1)anot = 0.

If not, can someone give me an example of the basis.

Thanks in advance