Answer:
encourage listeners to envision freedom everywhere.
Step-by-step explanation:
The most likely reason King uses allusions in this part of his speech is to encourage listeners to envision freedom everywhere.
The popular "I Have A Dream" speech made by Martin Luther King was primarily about his vision for the freedom and job availability for the black people and equality.
He made use of allusions and metaphors to let his listeners understand the way the blacks were treated in society and why there was an urgent need for equality, desegregation, civil rights, and freedom, amongst others.
He was passionately appealing to his listeners to envision freedom everywhere.