and the answer is...B
here is the explanation from kaplan:
Neurulation is the process of neural tube formation. The neural plate invaginates and forms a tube. This is
induced through a chemical message from presumptive notochord mesodermal cells, which develop from the
dorsal lip of the blastopore.
i also thought the answer was D, and when i looked on google for more info, i couldnt find much about it...