Final answer:
Military intervention is the correct answer as it is not an indirect strategy but a direct form of engagement that leads to immediate conflict.
Step-by-step explanation:
The question asks to identify which option is not an indirect strategy used to initiate conflict with partners. Among the given options, diplomacy (a), economic sanctions (b), and negotiation (d) are all considered indirect methods of handling conflicts that do not involve direct physical confrontation. Economic sanctions and diplomacy are tools often used to apply pressure and persuade another entity to change its strategy or behavior without resorting to combat. Negotiation is a peaceful method meant to resolve issues before they escalate into conflict. However, military intervention (c) is an example of a direct strategy, as it involves the deployment of armed forces, which is a direct form of engagement and often leads to immediate conflict. Therefore, the correct answer is that military intervention is not an indirect strategy used to initiate conflict with a partners.