‘Q’ will be the first part of the given sequence as it refers to the next action that takes place after the stopping of the bus in S1, that is, ‘A woman and a man got in together’. ‘S’ will be next as it is continuation with the previous statement which is clearly indicated from the pronoun, ‘they’. ‘R’ will come next as it describes the lady that got onto the bus, which is clear from the words, ‘The young woman was carrying a pet dog’. ‘P’ will follow ‘R’ as it takes us to the next action related to the subjects, that is, ‘The conductor came in and took the fares’. Hence, QSRP is the correct sequence. Thus, option (b) is correct.