(Please help) How does Emma Burke elaborate on the relief camps how does she explain the relief camps so that we have a clear idea of what it was like how does she add more detail fill out the table

Why was the united states motivated to establish the open door policy? a. the policy guaranteed american commerce with china. b. the policy supported the chinese nationalist cause. c. the policy led to a gain of american colonies in asia. d. the policy claimed damages from the chinese.