Answer:
A-
YES they are proportional because the answer every time is 5x
B- The x coordinate is growing by one and the y coordinate is growing by 5
C- for 0 t-shirts the y coordinate would be 0 as well, and for 5 shirts it would be 25 (5*5)
Focus on Math-
no it would not because instead of the equation looking like 5x it would look like 5x+4
Enjoy!!