A scalar matrix is a diagonal matrix in which all the diagonal elements are equal. In this case, the matrix has the diagonal elements $\sqrt{5}$, $\sqrt{2}$, and $\sqrt{5}$, which are not equal. Therefore, this is not a scalar matrix. However, it is a diagonal matrix and the definition of a scalar matrix requires all diagonal elements to be the same. So, this is not a scalar matrix, making it a symmetric matrix as it satisfies $A = A^T$ for this case. The correct answer is (D).