Respuesta :
I think the answer is C because in most professional writing you wouldn't address the audience (so D is out) and you wouldn't voice your opinion (A is out) and you would say I, me, my basically you wouldn't talk in first person (so A and B are out)
I would choose C. Hamlet is the only character who ever hears the ghost speak, and even he wonders at first if it really exists. Hope this helps!!