The traceur (a male parkour practitioner) must be very physically fit and agile in his movements.

why are parentheses, rather than dashes or commas, used in this sentence?

answers:
a. parentheses are being used because they set off longer, less-related parenthetical asides. b.parentheses are being used because they are setting off an aside that already contains commas. c.parentheses are being used because they are providing background or additional informationd. parentheses are being used to set off brief, closely-related parenthetical asides