'R' will be the first part of th given sequence as 'rich man' forms the central idea of the given order. 'S' will follow next as per the subject-verb agreement rule. 'Q' will come next as 'goes on' is used in the context of 'buying things'. 'P' will be the last part of the given order as 'already has' is used in connection to 'buying things'. Hence, RSQP is the correct sequence. Thus, option (b) is correct