Answer:
Option D.
Step-by-step explanation:
Note: The given function is incomplete. Consider the given function as [tex]M(t)=N(1+r)^t[/tex].
The number of members at month t is
[tex]M(t)=N(1+r)^t[/tex]
where,
N is the initial number of members.
r is the rate of increase.
t is number of months
Here, N is constant. So, option A is incorrect.
N is initial value and (1+r) is growth factor. So, option B is incorrect.
The given function is an exponential function.
The value of M is a product of N and a factor that does not depend on N.
Therefore, the correct option is D.