The correct sequence of stages in cell cycle is
(a) $\mathrm{G}_{1}, \mathrm{~S}, \mathrm{G}_{2}, \mathrm{M}$
(b) $\mathrm{G}_{1}, \mathrm{G}_{2}, \mathrm{~S}, \mathrm{M}$
(c) $\mathrm{M}, \mathrm{S}, \mathrm{G}_{1}, \mathrm{G}_{2}$
(d) $\mathrm{G}_{2}, \mathrm{G}_{1}, \mathrm{M}, \mathrm{S}$