Which Chicago architect, a pioneer of the skyscraper, declared 'form follows function' and designed the Wainwright Building in St. Louis?

• A Louis Sullivan ✓
• B Daniel Burnham
• C John Wellborn Root
• D William Le Baron Jenney

Louis Sullivan, mentor to Frank Lloyd Wright, articulated the principle 'form ever follows function' in his 1896 essay and is considered the father of the modern skyscraper.