Final answer:
The phrase from the negative counterclaim that contains the strongest use of pathos is 'since many states are already financially burdened'.
Step-by-step explanation:
The phrase from the negative counterclaim that contains the strongest use of pathos is 'since many states are already financially burdened'. This phrase appeals to the reader's emotions by evoking a sense of sympathy and understanding for the challenging financial situations of the states, which may make it difficult for them to cover all college fees for all students.