Which regression equation best fits these data ?

Answer:
C. [tex]y = -0.30\cdot x^{2}-0.48\cdot x+15.83[/tex]
Step-by-step explanation:
The best fit curve for the given set of points is the quadratic form, which is defined by:
[tex]y = A\cdot x^{2}+B\cdot x + C[/tex] (1)
Where:
[tex]x[/tex] - Independent variable.
[tex]y[/tex] - Dependent variable.
[tex]A[/tex], [tex]B[/tex], [tex]C[/tex] - Coefficient.
The coefficient associated with the second-power component determines whether vertex is an absolute maximum or not. The vertex is an absolute maximum if and only if [tex]A < 0[/tex], otherwise it is an absolute minimum. From image we notice that resulting fit curve will have an absolute maximum, then [tex]A < 0[/tex]. Hence, the correct answer is C.