A. \(AB=BC=AH=\dfrac{AD}{2}=\dfrac{2a}{2}=a\)
\(\Rightarrow A\left(0;0;0\right);B\left(a;0;0\right)\)
\(\Rightarrow\) Sai
B. \(C\left(a;a;0\right);D\left(2a;0;0\right)\)
\(\Rightarrow\) Đúng
C. \(S\left(0;0;2a\right)\Rightarrow\) Đúng
D. \(H\left(a;0;0\right)\Rightarrow\) Đúng