12. (4%) Please explain the Hall effect. Your explanation:      (12)

(b) \( (12\%) \) Find the bases for the four fundamental subspaces of \( \mathbf{A} \), namely, the nullspace \( N(\mathbf{A}) \), the nullspace \( N(\mathbf{A}^{\mathrm{T}}) \), the range \( R(\mathbf{A}) \), and the range \( R(\mathbf{A}^{\mathrm{T}}) \), respectively.