Is the following argument valid or not?
If Jan worked for Graham then either she graduated from Cornell or she was a family friend. Jan was no family friend and she didn’t work for Graham, so Jan didn’t graduate from Cornell.
a. Yes, it is valid.
b. No, it is not valid.
c. It is neither valid nor invalid because of an interpretational plurality.
d. It is not valid; it is not invalid; and it is not neither valid nor invalid.