Which statement is correct concerning how gastrulation in the frog embryo create

Which statement is correct concerning how gastrulation in the frog embryo creates body axes?

The blastopore defines the posterior end of the gut; the region where cells first move into it becomes the ventral side.
    The blastopore defines the anterior end of the gut; the region where cells first move into it becomes the dorsal side.
    The blastopore defines the posterior end of the gut; the region where cells first move into it becomes the right side.
    The blastopore defines the posterior end of the gut; the region where cells first move into it becomes the dorsal side.