In a long transmission line, consider the definitions below, and choose the correct relation between \(\mathbf{Z}_{\mathbf{C}}, \mathbf{Z}_{\text {S.C. }}\), and \(\mathbf{Z}_{\text {O.C. }}\). \(\mathbf{Z}_{\mathbf{C}}:\) Characteristic impedance \(\mathbf{Z}_{\text {S.C. }}\) : The impedance seen from the beginning of the transmission line if its end is short circuit \(\mathbf{Z}_{\text {O.C. }}\) : The impedance seen from the beginning of the transmission line if its end is open circuit 

1) \(\mathbf{Z}_{\mathbf{C}}=\mathbf{Z}_{\text {S.C. }}-\mathbf{Z}_{\mathbf{O . C}}\)

2) \(\mathbf{Z}_{\mathbf{C}}=\mathbf{Z}_{\text {O.C. }}-\mathbf{Z}_{\text {S.C. }}\)

3) \(\mathbf{Z}_{\mathbf{C}}=\sqrt{\mathbf{Z}_{\text {S.C. }} \mathbf{Z}_{\mathbf{O} . \mathbf{C}}}\)

4) \(\mathbf{Z}_{\mathbf{C}}=\frac{1}{2}\left(\mathbf{Z}_{\text {S.C. }}+\mathbf{Z}_{\text {O.C. }}ight)\)