Consider the discrete-time signal\(x\left( n \right) = {\left( {\frac{1}{3}} \right)^n}u\left( n \right),where\;u\left( n \right) = \left\{ {\begin{array}{*{20}{c}}{1,}&{n \ge 0}\\{0,}&{n < 0}\end{array}} \right.\) Define the signal y(n) ⇒ as y(n) = x(-n), -∞ < n < ∞Then, \(\mathop \sum \limits_{n = - \infty }^\infty y\left( n \right)\) equals

• A. \(- \frac{2}{3}\)
• B. \(\frac{2}{3}\)
• C. \(\frac{3}{2}\)
• D. 3