While sampling marine plankton in a lab, a student encounters ...

[Charlie]

While sampling marine plankton in a lab, a student encounters large numbers of fertilized eggs. The student rears some of the eggs in the laboratory for further study and finds that the blastopore becomes the mouth. The embryo develops into a trochophore larva and eventually has a true coelom. These eggs probably belonged to a(n)
A) chordate.
B) echinoderm.
C) mollusc.
D) nematode.
E) arthropod.

[camila]

Answer has to be C, trust me!

[Charlie]

Wonderful, you were right, thank you so much.