Match the ${{{C_P}} \over {{C_V}}}$ ratio for ideal gases with different type of molecules :
Molecule Type
CP/CV
(A) Monatomic
(I) 7/5
(B) Diatomic rigid molecules
(II) 9/7
(C) Diatomic non-rigid molecules
(III) 4/3
(D) Triatomic rigid molecules
(IV) 5/3