I think you have limited English skills, look at what you wrote:
If all the MP's closed down......that means all closed down
and all the MPA's retired except one.......that means only one is still working because all the others are retired
and you got to chose, who would keep?....well, only the one who isn't retired because she's the only one
It's a redundant statement.
or, are you asking who would I keep of the one's that are retired????
What the heck, confusing question that's for sure.