‘R’ will be the first part of the given sequence as the relative pronoun ‘who’ is used in order to give further information about ‘the actress’. P will come next in order to maintain the rule of subject-verb agreement. Q will come next as ‘selected as the best heroine’ is the logical phrase together. ‘S’ will be the last part as ‘best heroine of the year’ makes logical sense together. Hence, RPQS is the right sequence. Thus, option (a) is correct.