Final answer:
Horatio's response to Hamlet's letter highlights his strong allegiance to Hamlet over the king. He exhibits consistent loyalty and honesty in his actions towards Hamlet, underpinning their strong friendship and Horatio's supportive role.
Step-by-step explanation:
Horatio's response to Hamlet's letter indicates a strong sense of loyalty to Hamlet, rather than to the king. When Horatio receives Hamlet's letter informing him of his return to Denmark, he immediately goes to see Hamlet. This action, along with his participation in Hamlet's plans and his readiness to believe in Hamlet's concerns about the ghost, showcases his allegiance to Hamlet. He assists Hamlet in the attempt to expose Claudius, ultimately proving his loyalty lies with Hamlet over the king. Furthermore, Horatio's character consistently displays fidelity and honesty, qualities that Hamlet values and calls upon.