‘S’ will be the first part of the given sequence as it is in contrast to with the given sentence and begins with the word, ‘but’ , that is, ‘But the most famous among them is the Masai tribe’. ‘P’ will come next as it talks about the object of the previous statement, that is ‘The Masais were famous fighters’. ‘R’ will come next as it is in continuation with the previous statements and describes the object even more, which is indicated from the words, ‘They lived on the wide plains in Southern Kenya and Northern Tanzani Tanzania’. ‘Q’ will follow logically as it talks about their skills which relates to S6. Hence, SPRQ is the correct sequence. Thus, option (a) is correct.