theyeither choose to or there art is not famousanymore.
"Who shall retire" is correct. When asking a question about a person, use "who." "Which" is used to refer to things or a specified group of people.
Retire
The Undertaker will retire when he dies
After years of hard work, John decided to retire and spend more time with his family.
She wasn't going to retire yet.They decided to retire to bed for the night.
the band did not retire
when did sally ride retire
retire: jubilar(se)
he can resign not retire
most can retire after 20 years.
Retire is a verb.