The population of greenville is currently 50,000 and declines at a rate of 1.2% every year. this models:
exponential growth.
exponential logarithm
exponential decay

Exponential decay. Decay is clear, less. Exponential logarithm is contradictory.

So. the answer is
Exponential decay

Formula: 50000/1.12^years, which could be rewritten as 50,000/e^(number*years), and so it is exponential.

Declines means getting less in number

So its decay

Choice C