If \({\left( {\frac{{1 + i}}{{1 - i}}} \right)^x} = 1\), then

• A. x = 2n + 1, where n is any positive integer
• B. x = 2n, where is n is any positive integer
• C. x = 4n + 1, where n is any positive integer
• D. x = 4n, where is n is any positive integer