Answer:
D the amount of money he pays for each lunch
Step-by-step explanation:
In each lunch Devante has, he pays 2,50 $ according to:
Money in t = t₀   he has  35,50 $    paid 3 lunches and spent
35,50 - 28 Â = Â 7,5
Then the cost of each lunch is   7,5 / 3  =  2,5 $
After that
bought   5 lunches and spent  28  - 15,5  = 12,50
Again   12,5 / 5  =  2,5 $
Now the model for the situation is a straight line with a slope 2,5
In an  x , y cartesian system in which  y is money in the account  and x is the number of lunches, such a straight line will be
y  =  b  -  m*x    ( b the intercept on y  and  m the negative slope)
y  =  35,50 - 2,5*x
So  answering the question is lyrics  D  the amount of money he pays for each lunch