Which four?

The Williams sisters are obvious.

Kournikova, Strug, Kerrigan, and Harding I know just from having grown up in America in the 90s. They were all very famous for very, very different reasons.

Clark is super famous right now, as is Biles. Biles is more famous by me because she's from my home city. Ledecky I know because my family follows Olympic swimming. Kwan's name just stuck in my brain for some reason.

If I had to think of an eleventh athlete, it'd take me a while. There's another gymnast I could come up with, I'm sure. That really old one.