'S' will be the first part of the given sequence as per the subject verb agreement rule, that is, 'members walked out'. 'R' will be the next part as 'out of' forms a logical pairing together. 'Q' will come next as it states the reason of walking out, that is, to protest. 'P' will be the last part of the given order as 'protest against' in Q is used in connection to 'the ruling of the speaker'. Hence, SRQP is the correct sequence. Thus, option (a) is correct.