Hi All, I'm racking my brain right now with these SA questions, and I would greatly appreciate the community's help. While I can sort of diagram out the right answer, I don't exactly get why certain elements don't work.

For example:

If the support states that:

Don't Sleep -> Tired -> Prone to Mistakes

and the Conclusion is:

Don't sleep -> Fired

Why is the Sufficient Assumption: "Prone to Mistakes -> Fired" and not "Tired -> Fired"?