Sandra's ex-spouse earns significantly less than her. What portion of Sandra's income is taxable?

To determine the taxability of Sandra's income, it's important to understand how personal income is treated under tax regulations. All of Sandra's income is considered taxable unless specified otherwise by tax laws or deductions, such as those relating to alimony or specific tax credits.

Since the question specifies that her ex-spouse earns significantly less, it indicates a disparity in income but does not affect the taxability of Sandra's total income. When filing taxes, individuals report their total income, which includes wages, salaries, and other earnings, and then calculate adjustments, deductions, and credits as applicable. Therefore, the correct view is that the entirety of Sandra's income is subject to taxation.

Other options may suggest specific scenarios related to alimony or comparative income assessments, but they do not align with how income taxation is typically structured. Alimony's tax treatment may vary, especially from 2019 onward, where new tax laws changed how alimony is taxed for payers and receivers. The interpretation of just the difference in income or suggesting that her taxable amount could be zero does not reflect the standard tax implications of individual earnings.