$($Linear Programming$)$ The professor is hiring a teaching assistant $($TA$)$ and a research assistant $($RA$)$ for the next semester. The professor decides the number of working hours for TA $($x$)$ and the number of working hours for RA $($y$).$ The goal is to minimize the total salary using a linear programming method. Choose all the statements that cannot be incorporated in linear programming.

Group of answer choices

The ratio of the TA$$s working hours to the RA$$s working hours cannot exceed the sum of the TA$$s and the RA$$s working hours.

The university does not allow hiring TA for more than $50$ hours.

The professor pays a constant salary of $$350$ and $$400$ per hour for TA and RA$,$ respectively.

The ratio of the RA$$s working hours to the TA$$s working hours cannot exceed three.

The total number of working hours cannot exceed $200.$