解:因为\(A=\left \{ {{x|a{x}^{2}-ax+1<0}=\varnothing } \right \} \),所以不等式\(a{x}^{2}-ax+1<0\)的解集是空集,
当\(a=0\),不等式等价为1<0,无解,所以\(a=0\)成立.当\(a≠0\)时,要使\(a{x}^{2}-ax+1<0\)的解集是空集,则\( \left\{\begin{array}{l}a>0\\ △={a}^{2}-4a\le 0\end{array}\right.\),解得\(0<a≤4\).综上实数\(a\)的取值范围\(0≤a≤4\).
故选:D.