Resonance Structures of Sulfate Ion

I got this problem from a multiple choice set that didn't draw out all the lone pairs in the oxygens (which really annoys me), so I don't have much of a choice but to choose from the available choices...

Wikipedia: sulfate

Some authors suggest that expanded octets are less important contributors to the overall structure than previously thought.  I recall seeing an article in J. Chem. Ed. on this subject some time ago.

Thanks for the response. Does that mean that resonance structures without expanded octets usually contribute more than ones with expanded octets?

Doesn't that just mean there's resonance in the sulfate ion?

Only your structure A shows all electrons. Choose from other structures that one  with only  two minus charges ( and null charge on sulfur), draw all(!) electrons and all equivalence forms for it.

Wikipedia somewhat clears things up...thanks!! Is it usually true that resonance structures with expanded octets are less favorable in real life?

All S-O bonds in crystal structure of sulfates are the same. What does it mean?

Your structure A shows strictly octet at sulfur atom but many splitted charges.
Your structure C shows 12 electrons around S without no splitted charges. And this is the best - with other mesomeric structures (all 6 - showed in wikipedia)