President eisenhower's 1957 decision to send troops into little rock, arkansas, was in response to a) a violent strike of railroad workers. b) student protests against the war in korea. c) the bombing of an african-american church in little rock. d) local authorities' refusal to integrate central high school.

The correct answer is D) Local authorities refusal to integrate Central High School.

This controversy was a result of the "Little Rock 9." This referred to a group of 9 African American students trying to attend a previously all white school. Thanks to the Brown vs. Board of Education decision, it was now the national law that segregated schools must be desegregated. However, when these students in Little Rock Arkansas tried to do this, they were stopped by the Arkansas guard. To combat this, Presiden Dwight D. Eisenhower sent in the US National Guard to ensure that this school was in fact desegregated and the Little Rock 9 were able to attend.

the right answer is the third one: turnpikes went short distances to connect markets. turnpikes, also known as toll roads, were very important for trade and transportation (of people, goods and products) in the 19th century, coinciding with the expansion towards the west. they contributed significantly to the economic development of the united states.