I am troubleshooting a quantum computer that has access to a standard set of gates. I

believe that the $Z$ gate on a specific qubit may be malfunctioning and instead acting as an I

$($identity$)$ gate. Which circuit could I use to most easily test this hypothesis?

We will denote the potentially defective $Z$ gate as: $-Z$ or $I$

a$.|0$: or $I=\frac{O}{?}$

b$.|0$: or $I=$

c$.|0$: or $I=\frac{O}{?}$

d$.|0$: or $I=x$

e$.|0$: or $I=$

f$.$ None of these