Final answer:
The correct option is D). Retirement planning should include consideration of Social Security benefits, lifestyle adjustments, and healthcare costs. With expenditures on these programs projected to increase, there might be implications for their long-term sustainability and the possibility of significant policy changes.
Step-by-step explanation:
Retirement planning should encompass various factors beyond assessing changes in income. It entails considering Social Security benefits, making necessary lifestyle adjustments, and preparing for healthcare costs. All of these points fall into the category of 'D. All of the above' in terms of retirement planning elements. Millions of retired Americans rely on Social Security benefits, which are a crucial part of retirement income. However, with the long-term projections indicating a significant rise in Medicare and Social Security spending, it may prompt concerns over the sustainability of these programs and the potential need for increases in taxes, cuts in other spending, increases in retirement age, or the prospect of sizeable federal budget deficits.