Tính: \(A = \sqrt {{{\left( {\sqrt 5 - 1} \right)}^2}} + 1.\) \(B = \left( {2\sqrt 3 + \sqrt {20} } \right)\sqrt 3 - \sqrt {60} .\)
A.\(A = - \sqrt 5 \,;\,\,\,\,B = 4.\)
B.\(A = \sqrt 5 \,;\,\,\,\,B = 6.\)
C.\(A = 2\,;\,\,\,\,B = 5.\)
D.\(A = - 2\,;\,\,\,\,B = 4.\)