question_answer

Which of the following statements is/are correct? I. Adjoint of a unit matrix is a unit matrix. II. \[A(adj\,\,A)=(adj\,\,A)A=|A|\,\,I\] III. Adjoint of a symmetric matrix is symmetric. IV. Adjoint of a diagonal matrix is a diagonal matrix.

A)  I

B)  II

C)  I or II

D)  All statements are correct