Which one of the following Boolean expressions is NOT a tautology?

$(($p $->$ q$)($q $->$ r$))->($ p $->$ r$)$

$($p $$ r$)->($ q $->($p$$ r$))$

$($ p $$ q $$ r$)->($ r $$ p $)$

p $->($ q $->$ p$)$

All of the answers are tautologies.