Which American poet, known for his bold, celebratory style and collection 'Leaves of Grass', wrote 'Song of Myself' and revolutionised free verse?

• A Emily Dickinson
• B Robert Frost
• C Henry Wadsworth Longfellow
• D Walt Whitman ✓

Walt Whitman's 'Leaves of Grass', first published in 1855 and revised throughout his life, celebrated democracy, the body, and the individual self in a distinctly voice.