I need help with this question please

he following table displays the world’s population, in billions, since 1800.

Year Population (in billions)
1800 0.98
1900 1.65
1950 2.52
1990 5.27
2000 6.06
2010 6.79

Data from: The World at Six Billion
Desmos ProTip: You must click the “Log Mode” button in Desmos for this or any exponential regression problem.

a) Which type of model would best fit this situation?

b) Find a model to fit this situation where

P

P
represents the population in billions and

t

t
represents the years since 1800. Round to four decimal places.

=

c) Use your model from part b) to estimate what the population of the world will be in 2050. Round to the nearest tenth.

The population of the world in 2050 is estimated to be billion people.

d) Use your model from part b) to estimate when the population of the world will first be 9 billion. Round to the nearest year.

The population of the world is estimated to first reach 9 billion in the year .

For part B I got A=3.15 and B=1.00 but I am not sure how to put it in a equation can you help me finish this all.