What is the ratio of specific heats at constant pressure and constant volume for $NH_3$?

The molar specific heat of a monoatomic gas at constant pressure is (Universal gas constant $R = 8.3 \,J \,mol^{-1} \,K^{-1}$)

When heat $Q$ is supplied to a diatomic gas of rigid molecules at constant volume,its temperature increases by $\Delta T$. The heat required to produce the same change in temperature at constant pressure is:

For a gas molecule with $6$ degrees of freedom,which one of the following relations between gas constant '$R$' and molar specific heat '$C_{V}$' is correct?

Statement $A: C_P - C_V = R$
Statement $B: \frac{C_P}{C_V} = 1.67$

If $\frac{R}{C_v} = 0.67$,identify the gas.