Explanation:

- Office Expenses: These are costs related to the daily functioning of the office, including utilities, rent, and supplies. They are considered operating expenses because they are necessary for running the business.

- Selling Expenses: These include costs such as advertising, sales commissions, and distribution expenses. They are operating expenses since they are necessary to sell the products or services.

- Bad Debts: These represent receivables that cannot be collected. Often classified under operating expenses, they are part of the regular financial activities of a business.

- Loss by Fire: This is typically treated as a non-operating expense. It results from an unexpected event and is not part of the normal business operations.

Loss by Fire is not an operating expense.