Sally receives a $7,000 gift from her grandmother before going to college. before leaving she places a down payment on her classes of $500 and then spends $400 dollars a month while at school. write a function that models the amount she has in the bank per month while she is at college where y is the money in her account and x is the number of months she attends college.

a) y=400x+6500

b) y=−400x+7000

c) y=−400x+6500

d) y=500x+6500