a) \[\frac{8}{27}\]
b) \[\frac{27}{8}\]
c) \[\frac{1}{2}\]
d) \[\frac{2}{1}\]

Answer: b
Explanation: Boyle’s temperature, \[T_{b}=\frac{a}{Rb} \]  and critical temperature, \[T_{c}=\frac{8a}{27Rb} \]
\[\frac{T_{b}}{T_{c}}=\frac{27}{8} \]