'R' will be the first part of the given sequence as 'men of conscience' is the subject of the given sequence. 'Q' will come next as the possessive pronoun 'their' is used In the context of 'men of conscience' in R. 'S' will come next as the pronoun 'its' is used in the context of 'job' in Q. 'P' will be the last part of the given order as 'deserve all honour' is used in connection to 'nature' in 'S'. Hence, RQSP is the correct sequence. Thus, option (a) is correct.