Which company has the highest average production over the three years?

$$\eqalign{ & \text{A} = \frac{20 + 30 + 20}{3} \cr & \,\,\,\,\, = \frac{70}{3} \cr & \,\,\,\,\, = 23.33 \cr & \cr & \text{B} = \frac{40 + 30 + 50}{3} \cr & \,\,\,\,\, = \frac{120}{3} \cr & \,\,\,\,\, = 40 \cr & \cr & \text{C} = \frac{20 + 20 + 40}{3} \cr & \,\,\,\,\, = \frac{80}{3} \cr & \,\,\,\,\, = 26.66 \cr & \cr & \text{D} = \frac{60 + 30 + 40}{3} \cr & \,\,\,\,\, = \frac{130}{3} \cr & \,\,\,\,\, = 43.33 \cr} $$
So company D has the highest production.