Why Has the United States Tried to Deal with the Threat

Why has the United States tried to deal with the threat from Iran with diplomacy,rather than military options?

A) Diplomacy is likely to succeed since the Islamic world trusts and respects the United States.
B) Diplomacy is likely to lead Iran to isolationism,thereby removing the threat.
C) Military action would be more likely to lead to further radicalization of Muslims and terrorist retaliation.
D) Military action would be less likely to succeed,and could harm the cooperative approach taken by Iran toward the United States and its allies.