Which of the following statements is correct?

(a) \(C_{P}\) can never be less than \(C_{V}\)

(b) \(C_{P}\) is always equal to \(C_{V}\)

(c) \(C_{P}\) may be less than \(C_{V}\)

(d) \(C_{P}\) may be equal to or less than \(C_{V}\).