Parseval's theorem for discrete-time signals expresses energy equivalence between time and frequency domains as?

Parseval's theorem for discrete-time signals expresses energy equivalence between time and frequency domains as?

• A. ∑ |x[n]|^2 = (1/2π) ∫_{−π}^{π} |X(e^{jω})|^2 dω.
• B. ∑ |x[n]|^2 = ∫_{−π}^{π} |X(e^{jω})|^2 dω.
• C. ∑ |x[n]|^2 = (1/4π) ∫_{−π}^{π} |X(e^{jω})|^2 dω.
• D. ∑ |x[n]|^2 = (1/2π) ∫_{−π}^{π} |X(e^{jω})| dω.

Answer: (C)