Which of the following is a correct representation of the specification $"$If every user in the department is logged$-$in$,$ then there must be at least two servers running" in predicate logic. Let the domain of variable x be all users and the domain of variables y and z be all pieces of computing machinery at the university. Use D$($x$)$ for $"$x is a user in the department," L$($x$)$ for $"$x is logged$-$in$,"$ S$($y$)$ for $"$y is a server," and R$($y$)$ for $"$y is running."

Multiple choice question.