Answer:
B. 122.88
Explanation:
Since t is the number of years since 1910, we can find the t value we need for the equation by subtracting 1910 from 1980:
t = 1980 - 1910 = 70
Now, we can plug in 70 for t to find the amount of currency in 1980:

Thus, the amount of currency in 1980 according to the model was $122.88 billion