'Unique' is an adjective beyond comparison; hence, 'unique from' is an incorrect expression. This eliminates options (a) and (d). The verb hadn't is followed by 'any rather than 'no. This eliminates (a), (b) and (d). Since the clauses, 'Vikram's approach....' and 'he hadexpected.....' are in contrast, the connector used willbe 'but' rather than 'and'.