Which of the following led to increased tension between the united states and japan in 1937?

The Nanjing Massacre is the correct answer.

Explanation:

The tension between the US and Japan heightened because Japan sank USS Panay during its assault on Nanjing and a Japanese soldier also slapped the American Diplomat John M. Allison, US government exerted pressure on the Japanese government. Later the Japanese soldiers in Nanjing apologized to Allison. This incident came to be known as Allison Incident. The US government received many reports about the atrocities of the Japanese Army but the two countries were only focused on safeguarding their national interests.

explanation:

cause they can

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.