The answer is option B) Simple
This sentence is saying just the simple idea of you traveling alone over there is ridiculous. They're saying why even bother introducing the mere or simple idea?
Best Of Luck,

"I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justice."
Metaphor: King compares injustice and oppression to sweltering heat and freedom and justice to an oasis.