The step function is characteristic of the floor or ceiling functions, which map a real number to an integer. There's clearly a factor of 2, indicated by two units of y for every one unit of x.
The open and filled circles indicate, for example, f(1)=2, f(1.01)=4. That means we're rounding up, so we're using the ceiling function.

Answer: second choice
Answer B would be the best answer because it states how the prices differ and the 1 Liter bottle is able to go into the 2 liter bottle almost two times. Answer A could also be correct but B is more descriptive.
Answer:
C
Step-by-step explanation:
(x-3)+7