'P' will be the first part of the given sequence as the pronoun 'he' refers to 'the young traveller' in the opening part. 'R' will follow it next as it tells the thing produced from his waist. 'Q' will immediately follow it as the pronoun 'it' refers to the 'something' mentioned in the very previous part. It will then be followed by 'S' as 'fully loaded' is used in connection to 'navy revolver' mentioned in the very previous part. Hence, PRQS is the correct sequence. Thus, option (d) is correct.