Comprehensive and Detailed Explanation:

Business transactions are classified using five main types of accounts:

Asset -- Resources owned (e.g., cash, equipment, accounts receivable).

Liability -- Amounts owed (e.g., payroll taxes, loans).

Expense -- Costs incurred to operate the business (e.g., payroll expenses).

Revenue -- Income earned (e.g., sales, service fees).

Equity -- Owner's interest in the business (e.g., retained earnings).

Option A is incorrect because 'Inventory' is a type of asset, not a separate category.

Option C is incorrect because 'Cash' is a subcategory of assets, not a primary account type.

Option D is incorrect because 'Net Income' is the result of revenues minus expenses, not a separate account category.

GAAP Accounting Principles -- Types of Accounts

Payroll.org -- Payroll Accounting Classification