Correct the phrase written in parentheses

Now in a bizarre twist of fate, researchers have discovered that the normally vegetarian (sea urchins using a collective instinct, can turn) the (dining) tables on the predatory starfish;

Reponses:
A
NO CHANGE
B
sea urchins using, a collective instinct, can turn
C
sea urchins using a collective instinct can turn
D
sea urchins, using a collective instinct, can turn

C) sea urchins using a collective instinct can turn