What are considerations to think about when planning for retirement?

in order I would say, c,b,a

Lifestyle, item B. You have to be able to enjoy the things you like to do when you retire. If you like to garden, live in a place where you can do that most of the year.

Above all else, consider the person you retire with and what they like to do so they can also be happy.

All of the above along with risk tolerance, moral tolerance (if you are willing to invest in the sin industries of tobacco, gaming, defense, and alcohol), expected medical costs, how much you will travel when retired are a few major ones.

Good luck!

Simple answer- D!!! All are equally important.
Time to retirement allows adjustments to be made, whether you are talking about adding or subtracting what you are saving, supplementing your income so that you can retire earlier.
Planned quality of life- what are you gonna be doing? If you sit around you won’t live as long as if you are active. Own, rent, or move to retirement community.
Current savings- are you saving enough and is your savings earning the highest rate of return possible? Do you also contribute to an employer sponsored savings plan?
One thing you forgot about is Inflation! What will your nest egg support ten, fifteen, twenty and more years down the road? Your lifestyle could, significantly effect your nest egg.

Each and every one of these must be taken into account if you want to be sure that you have enough to support you during retirement. Hope this has helped.