'Ihe length of a pendulum is measured as $20.0 \mathrm{~cm}$. The time interval for 100 oscillations is measured as $90 \mathrm{~s}$ with a stop watch of $1 \mathrm{~s}$ resolution. The accuracy in the determination of $\mathrm{g}$ is
(a) $1 \%$
(b) $2 \%$
(c) $3 \%$
(d) $4 \%$