Neural tube formation occurs on___________?

• A. 18 to 23 days post fertilization and is the second stage of craiofacial development
• B. 28 to 38 days post fertilization and is the third stage of craniofacial development
• C. 42 to 55 days post fertilization and is the fourth stage of craniofacial development
• D. 17 the day post fertilization and is the first stage of craniofacial development