This statement is false.
In accounting, costs are classified into two main categories: product costs and period costs. Product costs are costs that are directly associated with the manufacturing of a product, and they include direct materials, direct labor, and manufacturing overhead. Office salaries, being an administrative expense, do not fall into the category of product costs; they are considered period costs as they are incurred regardless of production levels.
On the other hand, factory maintenance costs are generally considered part of manufacturing overhead. These costs are necessary for the maintenance of the factory, and thus, they are categorized as product costs since they are incurred to support the production process.
To summarize, office salaries are a period cost while factory maintenance is a product cost, making the statement actually false.