Which of the following statements is NOT true?

a$.$ Operating assets are often the most costly of the various types of assets acquired by an entity.

b$.$ In certain industries, such as computer software, operating assets are nonexistent.

c$.$ For manufacturing companies, property, plant, and equipment frequently represents a major percentage of a manufacturing company$$s total assets.

d$.$ For many companies, depreciation, amortization, and depletion are also among the largest items of periodic expense.