‘S’ will be the first part of the given sequence as it refers back tothe first statement with the word, ‘but’ and is in contrast to theprevious statement. ‘Q’ will come next as it tells what happened after the action was started in the previous statement which is clearly indicated from the word, ‘so’. ‘P’ will come next as it is in continuation with the previous statement which is clearly indicated form the word, ‘then’. ‘R’ will follow logically as it completes the meaning of the previous statement. Hence, SQPR is the correct sequence. Thus, option (a) is correct.