which is the correct formula for the combustion of S8 at STP, (a) or (b)?

Question

a) S8(s) + 4O2(g) ==> 4SO2(g)
b) S8(s) + 8O2(g) ==> 8SO2(g)

someone told me it is (a), but that is not balanced... or is it right?

please and thank you!!!!