’P’ will be the first part of the given sequence as it introduces the topic with the words, ‘dress fashions changed’. ‘R’ will follow ‘P’ logically as it completes the parts of the sentence, ‘light cotton textiles’. ‘S’ and ‘Q’ will also make a logical sequence as they contain the object to be compared. Hence, PRSQ is the correct sequence. Thus, option (a) is correct.