The correct answer is Sentence 4
Step-by-step explanation:
A word or phrase has an emotional connotation when it evokes emotions on the audience or it is associated with specific feelings, this includes positive and negative feelings the word evokes and that go beyond its literal meaning.
In the excerpt from Martin Luther King, the sentence with the strongest use of emotional connotation is sentence 4 "Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice" because the use of words such as "desolate valley" and "segregation" are linked to negative emotions especially in African Americans that have experienced this segregation; also, the use of "now is the time" and "racial justice" is related to feelings of hope. This makes all the sentence to be emotionally charged and evoke both positive and negative feelings.