Answer:
b. They warned them to stop expansionist actions or face potential U.S. intervention.
Explanation:
Japanese expansionism happened when Japan modernized, from a feudal country to a capitalist country, with certain policies of expansion. The Japanese believed that to meet Japanese needs, it was necessary to ensure a stable economic situation.
The United States opposed Japan's expansion policies and responded with threats to possible intervention and increasingly stringent economic sanctions designed to deprive Japan of the resources to continue its war in China.
Japan reacted by forging an alliance with Germany and Italy in 1940, known as the Tripartite Pact, which worsened relations with the United States. In July 1941, the US, Britain and Holland froze all Japanese goods when Japan completed its Indochina invasion, occupying the southern half of the country, further increasing tension in the Pacific.
