For which film did Charlize Theron win the Oscar for Best Actress?

For which film did Halle Berry win the Oscar for Best Actress? Who won the Oscar for Best Actress for 'The Hours'? For which film did Nicole Kidman win the Oscar for Best Actress? Who won the Oscar for Best Actress for 'Monster'? Who won the Oscar for Best Actress for 'Million Dollar Baby'? Who won the Oscar for Best Actress for 'Walk the Line'? For which film did Reese Witherspoon win the Oscar for Best Actress? Who won the Oscar for Best Actress for 'The Queen'?