The answer is a)
Let me know if you need an explanation
The population of a town has approximately doubled every 17 years since 1950.
the equation P=
where Po is the population of the town in 1950, is used to model the population, P, of the town t years after 1950.
When t=17 yrs
P=2
for 1 year
The equation becomes
P =
-------------(1)
Our original equation is
----------------------------------(2)
equating expression 1 and 2

Cancelling
from both sides we get

t/17=k
⇒k=t/17 is the solution.
A y-intercept is the value at which x = 0.
(4,0) is not a y-intercept because x = 4.
(-1, 1) is not a y-intercept because x = -1.
(0,0) is a y-intercept because x = 0.
(0, -7) is a y-intercept because x = 0.
(-2, 2) is not a y-intercept because x = -2.
(0, -0.25 is a y-intercept because x = 0.
When in doubt, graph it.
The 3rd and 4th choices are appropriate.
_____
This is what is known as a "logistic function." It is used to model population growth when there is a resource limit. It starts out exponential, but then slows as it reaches the "carrying capacity" of the environment. The lower asymptote is zero; the upper one is the carrying capacity of the resource--here 15/1 = 15.
Answer: the first 3 are 20, 5, 43. I dont know the others though