Basics of Bode Plot

Q. In a Bode magnitude plot, which one of the following slopes would be exhibited at high frequencies by a $4^{th}$ order all-pole system ?

1. $-80\text{dB/decade}$
2. $-40\text{dB/decade}$
3. $+40\text{dB/decade}$
4. $+80\text{dB/decade}$