Question

For the common ancestor of all the Bilateria, what was the fate of the blastopore?

neither (N)
deuterostomy (D)
protostomy (P)
It is impossible to tell from the data provided.

Answer 1

The information which is given above is not enough to describe what was the fate of the blastopore, so I am pretty sure that the last option is the best one : It is impossible to tell from the data provided.