Final answer:
Graph C represents the possible combinations of screws and nails that Jay can buy within his budget and with the requirement of having at least twice as many screws as nails.
Step-by-step explanation:
The graph that represents the possible combinations of screws and nails is Graph C.
Graph C shows a line that starts at the point (0,0), indicating no screws and no nails, and goes through points that represent different combinations of screws and nails.
The line passes through points such as (3, 1), (4, 2), (5, 2.5), and (6, 3), which satisfy the condition of having at least twice as many screws as nails and staying within the budget of $6.50.
The graph helps visualize the relationship between the number of screws and nails that Jay can purchase and ensures he meets the given requirements.