Cultured Pearls Are Made by

Cultured pearls are made by

A) cutting spherical balls from the thick shell of oysters and polishing them into circular beads.
B) dropping a grain of sand into the incurrent siphon of a pearl oyster.
C) tying off the labial palps.
D) growing oysters in high-calcium waters where they produce the pearls as unfertilized eggs.
E) placing an irritating particle under the shell mantle.