What term describes the slight convex curve deliberately built into the horizontal lines of the Parthenon, including its stylobate, to correct an optical illusion?

• A entasis ✓
• B anathyrosis
• C peristasis
• D sima

Entasis is the subtle outward swelling built into columns and the slight upward curve of horizontals in classical architecture, compensating for optical illusions that would make straight lines appear concave.