Rút gọn biểu thức: \(A = \dfrac{{{a^{\frac{4}{3}}} - 8{a^{\frac{1}{3}}}b}}{{{a^{\frac{2}{3}}} + 2\sqrt[3]{{ab}} + 4{b^{\frac{2}{3}}}}}.{\left( {1 - 2\sqrt[3]{{\dfrac{b}{a}}}} \right)^{ - 1}} - {a^{\frac{2}{3}}}\).
A.\(A = 0\)
B.\(A = a\)
C.\(A = 1\)
D.\(A = 2a\)