Which type of items may appear in the bottom section of the income statement that accountants deem unusual and infrequent?

The correct answer is nonrecurring items, which are defined as expenses or revenues that are not expected to occur in the normal course of business operations or that happen infrequently. These items might include losses from natural disasters, gains or losses from the sale of a significant asset, or unusual expenses stemming from legal settlements.

Including nonrecurring items in the bottom section of the income statement allows users of financial statements to assess the ongoing performance of the company without the distortion of these unusual events. By segregating these items, stakeholders can get a clearer view of a company's underlying profitability and can make more informed decisions based on its core operational results.

This distinction is important for financial analysis because it aids in forecasting and understanding a company's future earnings potential, without the noise created by these isolated gains or losses.