What is the largest value of $n$ for which there exists a set $\left\{A_{1}, \ldots, A_{n}\right\}$ of (distinct) nonzero matrices in $\mathrm{M}_{2}(\mathbb{C})$ such that $A_{i}^{*} A_{j}$ has trace zero for all $1 \leq i < j \leq n?$
- $1$
- Greater than $1$ but at most $4$
- Greater than $4$ but finite
- $\infty$