Given:
That the surface area of a sphere is equal to the volume of the sphere.
[tex]\begin{gathered} \text{The surface area of a sphere is given by:} \\ A=4\pi r^2 \\ \\ \text{The volume of a sphere is given by:} \\ V=\frac{4}{3}\pi r^3 \end{gathered}[/tex]If area is equal to volume, then;
[tex]\begin{gathered} A=V \\ 4\pi r^2=\frac{4}{3}\pi r^3 \\ C\text{ ross multiplying,} \\ 4\pi r^2\times3=4\pi r^3 \\ 12\pi r^2=4\pi r^3 \\ \text{Dividing both sides by }4\pi r^2\text{ to get the radius,} \\ \frac{12\pi r^2}{4\pi r^2}=\frac{4\pi r^3}{4\pi r^2} \\ 3=r \\ r=3\text{units} \end{gathered}[/tex]Therefore, the length of the radius is 3units.
The correct answer is option A.