If P and M share a specialty then P must not be in 1992.
So P is in 1991 or 1990. That means P is beside O, and therefore P can’t share a specialty with O.
A doesn’t have to be true since P could go in 1991.
B could be false, because P could also go in 1990.
C could be false, because P could go in 1991 along with R.
D must be false. We can never have more than one year with two professors (the year with P.)
E must be true: P can’t go in 1992 and therefore P is hired before S. E is CORRECT.
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