Answer: It's about achieving your goals, no matter the situation.
Explanation:
You know the meaning of the word "exodus" ? Well, basically it's the march that a population perform from one place to another, looking for better opportunities or even a different life style.
This metaphor talks about how anyone can cross through rivers, mountains and valleys in order to achieve an specific goal.
A clear example? Self-improvement.
Not even the overwhelming heat of a "desert" can stop human will.
Excerpt of The Grapes of Wrath:
And men with hoses squirt kerosene on the oranges, and
they are angry at the crime, angry at the people who have
come to take the fruit. A million people hungry, needing the
fruit-and kerosene sprayed over the golden mountains.
And the smell of rot fills the country.
The answer is A.
The narrator mainly feels bitter toward those he interacts with in town.