b
Rotational kinetic energy \((K)=\frac{1}{2} I \omega^{2}=\frac{1}{2} M R^{2} \omega^{2}\)

\(\therefore \frac{\Delta K}{K} \times 100=\frac{\Delta M}{M} \times 100+2 \frac{\Delta R}{R} \times 100+2 \frac{\Delta \omega}{\omega} \times 100\)

\(=2 \%+(2 \times 1 \%)=6 \%\)