Consider the following relations for emf of an electrochemical cell

$\left(\mathrm{i}\right)$ EMF of cell = (oxidation potential of anode) - (Reduction potential of cathode)

$\left(\mathrm{i}\mathrm{i}\right)$ EMF of cell = (oxidation potential of anode) + (Reduction potential of cathode)

$\left(\mathrm{i}\mathrm{i}\mathrm{i}\right)$ EMF of cell = (reduction potential of anode) + (oxidation potential of cathode)

$\left(\mathrm{i}\mathrm{v}\right)$ EMF of cell = (oxidation potential of anode) - (oxidation potential of cathode)

Which of these expressions are correct?