For a feedback amplifier, the open loop transfer function has three poles at $100 \; k \; \mathrm{rad} / \mathrm{s}, 1 \; \mathrm{M} \; \mathrm{rad} / \mathrm{s}$ and $10 \; \mathrm{M} \; \mathrm{rad} / \mathrm{s}$. The low frequency open loop gain is $1000$ and the feedback factor $(\beta)$ is $1$. Use Bode plots to determine the phase margin of the amplifier. Is the amplifier stable?