Answer:
Step-by-step explanation:
Given are three vectors in set B.
To show that B is dependent
The determinant
![\left[\begin{array}{ccc}1&0&1\\0&1&2\\2&-1&0\end{array}\right] \\=1(2)-1(2) =0](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%261%5C%5C0%261%262%5C%5C2%26-1%260%5Cend%7Barray%7D%5Cright%5D%20%5C%5C%3D1%282%29-1%282%29%20%3D0)
Hence vectors are dependent
b) The given equation 
Let us try parametrically
These 3 vectors are collinear and hence equation would be

c) Basis for B would be only 2 dimensional
i.e. any two vectors out of 3 form basis
The basis would be (1,0,1) and (0,1,2)