Final answer:
The tone of Marcellus' statement, "Something is rotten in the state of Denmark," can best be described as ominous due to the country's impending war and the troubles haunting the royal family.
Step-by-step explanation:
The tone of Marcellus' statement, "Something is rotten in the state of Denmark," can best be described as ominous. This is because the country is on the verge of war and Denmark's royal family is haunted by troubles.