The correct answers are C. Interest income and D. Gain on sale of assets . Net income increases when revenues and gains increase, while it decreases when expenses and losses increase. Interest income is a type of revenue or other income that adds to earnings. Gain on sale of assets also increases net income because it represents the amount by which proceeds from the sale exceed the asset’s carrying value. OpenStax notes that the income statement includes revenues, expenses, gains, and losses in measuring financial performance.

Option A. Income tax expense decreases net income because it is an expense. Option B. Cost of sales also decreases net income because it is a major operating expense deducted in arriving at gross profit and ultimately net income. Gains and interest income improve profitability, whereas expenses reduce it. This distinction is fundamental in preparing and interpreting the income statement. Therefore, the two items that increase net income are Interest income and Gain on sale of assets , making C and D the correct answers.