(i) Yeltsin worked as a Mayor of Moscow.
(ii) Yeltsin was returned to power with overwhelming support of a Moscow in 1899.
(iii) For twelve days, the Soviet Union continued to exist only in name.
(iv) On 28th February 1991, USSR was formally dissolved.
(a) (i) and (ii) are correct
(b) (i), (ii), (iii) are correct
(c) (i) and (iii) are correct
(d) All the four are correct.