Answer:
B. Zero
Step-by-step explanation:
Here the number of downloads between minute 14 and minute 15 is 3000. The number does not increase or decrease so the slope is zero.
The slope of line between two points (x₁, y₁) and (x₂, y₂) is given by
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/25uxp4sblay2143idvgkz738ukrk1vzo5g.png)
Here,
![m=(30-30)/(15-14)\\\Rightarrow m=(0)/(1)=0](https://img.qammunity.org/2019/formulas/physics/high-school/krtyfg4qy23wstb59lwj3hgfentb0qynhi.png)
The slope of a function is given by the differential of the function.