The correct answer is (A) Disc

The object is Disc.

=$$v = \sqrt{\frac{2gh}{1+\frac{k^{2}}{r^{2}}}}$$

=$$v^{2} = {\frac{2g 3v^{2}}{4g (1+\frac{k^{2}}{r^{2}})}}$$

= $$1 + \frac{k^{2}}{r^{2}}$$

=$$\frac{3}{2}$$

=$$k^{2} = \frac{1}{2}r^{2}$$

Hence prooved. The object is Disc.

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