This is an extremely hard question to answer, it most importantly depends on what speed you fly, you must put into thoguht that flaps can’t be extended in too high speeds as they would be damaged IRL if such procedure would be used. It also depends on which aircraft you fly.
Usualy the lowest flap option is (most commonly) fit for a maximum IAS of 215kts
The second lowest flap otion is usualy around 180-190kts IAS from my understanding, as I said it really depends on the aircraft.
The medium flap option is around 170kts or even 180kts IAS depending.
The highest option is around 150-165kts IAS depending.
But as I said it ALL depends on the aircraft, the airport you´re landing it, speed restrictions by ATC, your decent procedure etc.
Don’t forget to trim correctly! :)
EDIT: Altitude has no meaning! Speed and what you need to stabilize your aircraft comes first!