Final answer:
The slope of the total cost line on a CVP graph signifies the variable cost per unit, which illustrates the increase in total costs associated with each unit of output produced.
Step-by-step explanation:
When preparing a CVP (cost-volume-profit) graph, the slope of the total cost line represents the variable cost per unit. The total cost consists of both fixed and variable costs, and at zero production, only fixed costs are present.
As production increases, variable costs are added to the fixed costs, and the total cost rises proportionally with the quantity of output produced. The slope of the total cost line on a graph indicates how much the total cost will increase with each additional unit produced, which directly reflects the variable cost per unit.