The graph shows the results of an investigation into the relationship between the concentration of reactant A A\,A and the initial rate of reaction.

Which option best describes the results of the investigation?
Concentration of reactant AAA is directly proportional to the initial rate of reaction.
Concentration of reactant AAA is inversely proportional to the initial rate of reaction.
There is a non-linear positive correlation between the concentration of reactant AAA and the initial rate of reaction.
There is an inverse correlation between the concentration of reactant AAA and the initial rate of reaction.