‘Q’ will be the first part of the given sequence as it talks about where is the action was performed. P will follow Q as Q needs a verb as per the subject-verb agreement rule; P contains the verb ‘decided’. ‘S’ will come next as it starts with the word, ‘till’ which is a less formal way of saying ‘until’ which means ‘up to the point in time or the event mentioned’. Hence QPSR becomes the right sequence of words. Hence, option (a) is correct.