Resource Consulting Is Studying the Costs of Several Clients, and Has

Resource Consulting is studying the costs of several clients, and has found graphs of cost behaviour patterns would appear as follows:
1. A straight line that gradually slopes upward to the right
2. A curvilinear line that gradually slopes upward to the right
3. A straight line that is parallel to the graph's horizontal axis
4. A straight line that gradually slopes downward to the right
5. A curvilinear line that gradually slopes downward to the right
6. A straight line that gradually slopes upward to the right and then, at a specific point, flattens out to run parallel to the horizontal axis
7. A series of straight lines that appear to resemble a set of steps
8. A straight line that runs parallel to the graph's horizontal axis and then, at a specific point, drops to a lower level
Unless told otherwise, assume that the horizontal axis represents total activity and the vertical axis represents total cost.
Required:
For items A-F below, indicate the number of the graph that best represents the cost behaviour pattern described. Note: Graphs can be used more than once, and not all graphs need be used.
$\begin{array} { l l } 15,000 \text { to } 29,999 \text { units } & \$ 5 \text { per unit } \\30,000 \text { to } 44,999 \text { units } & \$ 6 \text { per unit } \\45,000 \text { to } 59,999 \text { units } & \$ 7 \text { per unit }\end{array}$