Which one among the following is the correct option for right relationship between \( C _{ P } \) and \( C _{ V } \) for one mole of ideal gas?
(A) \( C _{ P }+ C _{ V }= R \)

(B) \( C _{ P }- C _{ V }= R \)
(C) \( C _{ P }= RC _{ V } \)
(D) \( C _{ V }= RC _{ P } \)