A.\(D = \left( { - \infty ;0} \right] \cup \left[ {3; + \infty } \right)\)           
B.\(D = \left( { - \infty ;0} \right) \cup \left( {3; + \infty } \right)\)
C.\(D = \left( {0;3} \right)\)                           
D.\(D = \left[ {0;3} \right]\)