Final answer:
Denmark is preparing for war due to royal succession and political unrest.
Step-by-step explanation:
Denmark is preparing for war due to A) Royal succession and C) Political unrest. Royal succession refers to the process of determining the next ruler or monarch, which can often lead to conflict and potential war. Political unrest, which can arise from various factors such as social inequality or disagreements among political factions, can also contribute to a country's preparation for war.