The pressure and density of a diatomic gas $(\gamma = \frac{7}{5} )$ changes adiabatically from $(P, d)$ to $(P', d')$. If $\frac{d'}{d} =32$. Then $\frac{P'}{P}$ is :

Question

( A ) $256$
( B ) $128$
( C ) $32$
( D ) $\frac{1}{128}$