Correct option is: A) 2r
Let radius of the base of the cone be R.
\(\because\) Volume of cone = volume of sphere
= \(\frac 13 \pi R^2 h\) = \(\frac 43 \pi r^3 h
\)
= \(R^2 = \frac {4r^3}{h}\)
= \(R^2 = \frac {4r^3}{r}\)( \(\because\) h = r)
= \(4r^2\)
= \((2r)^2\)
\(\therefore\) R = 2r
Hence, the radius of the base of the cone is 2r.