Which of these factors was not a major reason for japan’s expansion of its empire in the late-19th and early-20th

Which of these factors was not a major reason for japan’s expansion of its empire in the late-19th and early-20th centuries? a) the need for a stable source of raw materials b) the need to create a defensive buffer from china and russia c) direct competition with the united states for control of the region d) a sense of ethnic and national superiority over countries in the region