In case of which soft drink was the average annual sale minimum during the period 1988-1993?

Answer: Option C

$$\begin{array}{rl}& \text{Average annual sales of Dew-drop}\\ & =\frac{10+15+15+15+30+25}{6}\\ & =\frac{110}{6}\\ & =18.3\text{ lakh bottles}\\ & \text{Average sales of Cool-up}\\ & =\frac{120}{6}\\ & =20\text{ lakh bottles}\\ & \text{So, minimum sales = Dew-drop}\end{array}$$