Since the answer is "both", you're probably think that that's the stupidest question anyone could ask. And you'd probably be right.
However with race & gender becoming ever more prominent in the US Presidential primaries there are ever greater demands for people to support a candidate not because of policies but because they are the same race or gender as the voter. So what happens when they are the same as two candidates?
normblog: Oprah or farce? notes that Oprah Winfrey's endorsement of Barack Obama has led to supporters of Hillary Clinton makind accusations of treachery against her fellow women! See also The Sunday Times: Women turn on 'traitor' Oprah Winfrey for backing Barack Obama.
Now I don't know much about Oprah's particular brand of politics so I can't comment on which candidate is the natural choice for her. But I find it hypocritical of her detractors to attack her not for apparently choosing a candidate on grounds of identity, but for choosing the wrong identity!