Due to its shape, and its asymptotic tendency to go towards 0 as x goes to minus infinity and go towards infinity as x goes to infinity, the graph presented seems to be an exponential function, an exponential function has the following form:

The only exponential function included is g(x) = -2*, then, this function is the one that represents the graph, one way to quickly prove it is by replacing 0 for x into the function, as you can see in the graph, the curve goes through (0, -1), then when we replace 0 for x into the function we should get -1, like this:

Then, the correct answer is option A