Answer:
a. make multiple fixes.
Step-by-step explanation:
When we are troubleshooting firewalls we should not make multiple fixes after attempting a fix because it will not be beneficial for the security purpose.
We can repeat the failure after attempting the fix because we can fix it but a person with right mind won't be doing that.
We can test after each attempt that it is working properly.
We can also reverse or undo the solution failures after making a fix.