9514 1404 393
Answer:
b. iii, v, and vi
Explanation:
We assume your equations are intended to be P=(something) where the something has a final factor of ( )^t.
The final factor is called the "growth factor". Subtracting 1 from it gives the "growth rate". When that value is negative, the population is declining.
Equations (iii), (v), and (vi) have growth rates that are negative, so those represent towns decreasing in size.