A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of \(2 \mathrm{~mm}\) from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, its has a frequency of vibration of 10 radians/second. When the shaft is rotated a 300 revolutions per minute, it will whirl with a radius of

(a) \(2 \mathrm{~mm}\)

(b) \(2.25 \mathrm{~mm}\)

(c) \(2.50 \mathrm{~mm}\)

(d) \(3.00 \mathrm{~mm}\).