When you plot these points you can see that the curve starts out high at a y value of 91, and as the x values grow slowly, by increments of 1, the y values drop rapidly. It resembles a downward curve. By that I could tell that it wasn't linear because it definitely wasn't a straight line; it wasn't either one of those quadratics because long story short the vertices don't match the graph. Therefore, by elimination I chose and then tested the exponential function. For the first couple of points (0, 91) and (1, 70),
. Anything raised to a power of 0 is 1 and 91*1=91. For the second point,
and 91*.77 = 70.07. Therefore, your choice is the second one down.