Answer:
1) 20%
2) Choice a.
Step-by-step explanation:

1)
is the population initially.
is the population after a year.
represents the population increase factor.
So let's evaluate that fraction:


0.2=20%
2) Let's figure out the population growth in terms of months instead of years.

We want t to represent months.
A full year is 12 months, in a full year we have that 
So we want a new P such that
since 12 months equals a year.
Let's look at the functions given to see which gives us this:
a) 
b) 
c) 
d) 
So a is the function we want.
Also another way to look at this:
where
is in years.
where
is in months.
And 