Final answer:
Hamlet is speaking to himself about his beliefs in the existence of spirits and his disagreement with Polonius.
Step-by-step explanation:
The answer to the question "In the given passage, who is speaking to whom?" is 4) Hamlet is speaking to himself. In the given passage, Hamlet is speaking about his belief in the existence of spirits and how many people have seen them. He disagrees with Polonius' opinion that seeing a ghost is just a figment of the imagination. Hamlet's thoughts are expressed through a soliloquy, which is a speech in which a character speaks to themselves, revealing their inner thoughts and feelings.