A solution containing one mole per litre each of A'X, B'X2, C'X2 and D'X2 is electrolyzed using inert electrodes. The values of standard potential for reduction reaction of A+/A, B2+/B, C2+/C and D2+/D are +0.80 + 0.34, –0.76 and –1.66 volts respectively. The correct sequence in which these metals will be deposited on cathode is
1
A', B', C', D'
2
D', C', B', A'
3
A', C', B', D'
4
D', B', C', A'