Which of the Following Indicates the Sequence of Steps in Neurulation

Which of the following indicates the sequence of steps in neurulation?

A) A neural plate portion pinches inward, starting the formation of the neural grove, the two sections of the neural plate come together, the neural grove completely closes off as the neural plate becomes the neural tube.
B) A neural plate portion pinches outward, the two sections of the neural plate join together and a neural tube is formed with the pinches.
C) Two sections of a neural plate are joined together through the electrical signals of the synapse, and form a neural tube.
D) None of the alternatives are correct.