Cho hàm số \(f\left( x \right) = \frac{{2x + a}}{{x - b}}\left( {a,b \in R,b \ne 1} \right)\). Ta có \(f(1)\) bằng:

A. \(\frac{{ - a - 2b}}{{{{\left( {b - 1} \right)}^2}}}\)

B. \(\frac{{  a - 2b}}{{{{\left( {b - 1} \right)}^2}}}\)

C. \(\frac{{ - a + 2b}}{{{{\left( {b - 1} \right)}^2}}}\)

D. \(\frac{{ a + 2b}}{{{{\left( {b - 1} \right)}^2}}}\)