The correct answer is option a.)
.
The formula for the volume
of a cone is given by
, where \(r\) is the radius of the base and
is the height. In this case, the height
is twice the radius
, so
.
Substitute
into the volume formula:
Simplify further:
Thus, the expression representing the volume of the cone is \(\frac{2}{3} \pi x^3\).
Therefore, the correct answer is:
a.
This expression accurately represents the volume of the cone in cubic units.