Due to the necessity of living on a fixed income, many retirees find it difficult to
a. afford to keep their large homes
b. maintain their old standard of living
c. pay for unexpected expenses
d. all of the above

If they have a fix income, then unexpected expenses will be very hard for them: option c is in any case correct.

This fix income is usually lower than before retiring, which is why they also struggle to keep their houses and maintain the standart of living.

The correct answer is d. All of the above

You could solve them by trying something new that everyone can agree on or make a decision too.