S will be the first part of the given sequence as ‘when Shakespeare was born’ is a logical and correct phrase together. P will come next as the usage of ‘but’ here shows a contrast between what is known and what is not known. Q will come next as ‘exact date of death’ is used in relation to ‘know’ in P. R will be the last part as ‘for certain’ is used in relation to knowing the exact date of his death. Hence, SPRQ is the right sequence. Thus, option (a) is correct.