What is the chemical formula of chlorophyll a?

• A. C₄₅H₇₂MgN₄O₅
• B. C₅₅H₇₂MgN₄O₅
• C. C₅₅H₇₂MnN₄O₅
• D. C₄₅H₇₂MnN₄O₅