I wouldn't ,as a rational and reasonable being, I should consider all possibilities, until we have solid proofs that favors one of them.
A and D are both equally logical, reasonable and possible.
But no proofs to support any of them ,so this will be fixed to 50/50 chance.
Like the Schrödinger's Cat.
http://www.youtube.com/watch?v=IOYyCHGWJq4