It can be considered as Greek mythology.
Is - two billion dollars is a unit, one unit so it is singular and you use the singular verb
think - scientists is a plural, therefore, you must use the plural verb form of think
The answer is:
3. It helps establish the idea that Didion's experiences in New York feel somewhat surreal to her now, like those of a character in a movie. <span> </span>
The answer is the second one, B. The other ones are obviously opinions, and the only one that comes close is C. However, many people have different ideas about how things should be handled by citizens, making C incorrect.