Two-phase simplex — a lingering zero-valued artificial signals degeneracy

Consider the auxiliary LP problem for two-phase simplex method, $\text{Max }Z^\ast=\sum_{i=1}^m(-1)A_i$ subject to $\sum_ja_{ij}x_j+A_i=b_i$, $x_j,A_i\ge0$. If Max $Z^\ast=0$ and at least one artificial variable is present in the basis (necessarily then at level $0$) then the original L.P. problem has: