Answer
A) Neither a linear nor an exponential function would be suitable.
B) We can not model the population as linear or exponential.
Work Step by Step
A) If we assume that the population is linear, the population in 2013 would be
$$
18,500+250 \cdot 10=21,000
$$ On the other hand, if we assume an exponential model, the percent rate would be $250 / 18,500 \approx 0.013514=1.351 \%$. The population in 2013 would be
$$
18,500(1.013514)^{10} \approx 21,158
$$
Clearly, neither a linear nor an exponential function would be suitable.
B) We can not model the population as linear or exponential.
