dative bond sulphur dioxode?

i've heard that there's a dative bond in sulphur dioxide in one or both of these diagrams.
A)

or
B)

I can kind of see it 'cos e.g. if we look at "B", the Oxygen could be seen to have 6 dots + two for the bond because the bond is dative. So 8. But then i'm thinking that for each atom maybe two electrons are counted for each bond anyway.
I know in some cases like "A", Sulphur can take 10 electrons.
But i'm confused as to how we determine if there's a dative bond or not?