Final answer:
The subject of the question is the annual convention that furniture manufacturers attend to categorize costs. The likely answer is the Industrial Cost Accounts Convention, which discusses direct and indirect costs as well as variable and fixed costs.
Step-by-step explanation:
Total costs are the sum of fixed plus variable costs. In the context of furniture manufacturers like Cooper Furniture, an annual convention that deals with cost categorization is likely to be the Industrial Cost Accounts Convention. At this convention, manufacturers discuss and categorize costs as direct or indirect and variable or fixed. For example, the convention may cover topics such as how to classify the cost of raw materials or production machinery. Such conventions aim to provide insights into cost management strategies and help businesses make informed decisions.