To be linear, you'd need a fixed increase in the y-values for a constant increase in the x-values. As x increases by 1 in each new point, your y-values increase by 1, 3, 5, and 7 respectively. That is not the same increase each time. This is not linear.
To be exponential, you need a fixed percent increase in the y-values between the points. From (-2,-16) to (-1,-15), your increase is 1/16 or 6.25%. From (-1,-15) to (0,-12), your increase is 3/15 or 20%. That is not a constant percent increase.
The only option left is quadratic.
To find the function, start with c = -12, based on the point (0,-12).
This gives you f(x) = ax^2 + bx -12
Next plug in (2,0) into f(x): 0 = 4a + 2b - 12
And plug in (1,-7) into f(x): -7 = a + b -12
You now have two equations with two unknowns.
Solve equation 2 for a:
5-b = a
Substitute that into equation 1
0 = 4(5-b) + 2b - 12
0 = 20 -4b + 2b - 12
-8 = -2b
4 = b
Substitute that b-value into 5-b=a
5 - 4 = a
1 = a
You have your three values and have your function:
f(x) = 1x^2 + 4x - 12 or f(x) = x^2 + 4x - 12
You can confirm that the other points also fit with this function.