Assertion (A) : If A = $\left[\begin{array}{ccc}\mathrm{x}& 3& -10\\ -3& \mathrm{y}& 9\\ 10& -9& \mathrm{z}\end{array}\right]$ is a skew symmetric matrix then Tr(A)=0.

Reason (R) : If A is a skew symmetric then all the elements in a principal diagonal are equal to zero.