What was a major reason for japan’s invasion of manchuria

While the Disarmament conference was going on, the Japanese invaded Manchuria. The Japanese invasion on 18th September 1931 of Manchuria signaled the end of apparent internationals stability. Though only one week earlier, Viscount Cecil, on behalf of the British government, addressed the Assembly of the League of Nations, saying, "there has scarcely been a period in the world's history when war seems less likely than it does at present." The Chinese appealed for help to the League on 22nd September! The onus of responsibility for action to oppose the Japanese aggression fell on the British, since they were the only major power with vested interests in the region. The event coincided with the crisis over the gold standard, whilst the Washington naval treaty had given the Japanese naval superiority in the region, which the British were unable to counter since they had not developed Singapore into a naval base. Foreign minister, Sir John Simon, sought to reconcile China and Japan at Geneva where the League met. He initiated a commission headed by Lord Lytton to investigate the rights and wrongs of the matter. After touring the Far East the commission reported at the end of 1932 that the Japanese grievances were justified, and, whilst the report condemned the Japanese use of force, Japan herself was not sanctioned. However, Japan withdrew from the League when the Lytton report was adopted. The Chinese accepted the loss of the province and concluded the truce of Tangku with Japan in 1933. Thus, Britain rid itself of the responsibility for enforcing the covenant of the League against Japan. It was inconceivable that Britain could act alone, and the United States would not join Britain in any action, since they had the bulk of the trade with Japan.

Correct textbook answers would be 1,3, and 5