Answer:
radius is the other quantity needed, which appears listed as option C in the list of possible answers.
Explanation:
Recall that the volume of a cone is given by the formula:
![Vol=(1)/(3) B\,*\, H](https://img.qammunity.org/2021/formulas/mathematics/middle-school/qj6hstzka6rmvm0hlszlygxfhg5vvevbyg.png)
where B is the area of the base:
![B=\pi\,R^2](https://img.qammunity.org/2021/formulas/mathematics/middle-school/r02qz56xu4etxznekfsi17nwln9m6tmy0g.png)
with R being the cone's radius at the base, and H the cone's height.
The formula for the surface area of the cone also needs the size of the radius.
Therefore, the radius is the other needed quantity.