I'm stuck in the next problem,

Let $n$ a positive integer and $V=M\_n(\mathbb{C})$. We define the inner product by $\langle A,B\rangle=\operatorname{tr}(A^t\overline{B})$. Let $W$ the subspace of $V$ such that if $A\in W$, then $\operatorname{tr}(A)=0$.
Find $W^\perp$.

Can you help me?

Greetings.