Final answer:
The excerpt where Hamlet sarcastically suggests King Claudius to look for Polonius in heaven or in hell, indicates that Hamlet believes Claudius is immoral.
Step-by-step explanation:
The best evidence that Hamlet believes King Claudius is an immoral person comes from the section where Hamlet speaks to Claudius after having disposed of Polonius's body. Hamlet's use of dark humor and indirect criticism towards Claudius when answering about the whereabouts of Polonius showcases his belief in Claudius's immorality. This is evident in the lines, 'In heaven; send hither to see: if your messenger find him not there, seek him i' the other place yourself', and, 'if you find him not within this month, you shall nose him as you go up the stairs into the lobby'. The sarcastic suggestion that Claudius should look for Polonius in heaven or perhaps in hell, and the implication that Claudius will eventually find the rotting corpse of Polonius by its smell, all point to Hamlet's disdain and moral judgment of the king.