The correct option is D Placoid scale with ventral mouth
Chondrichthyes is one of the class under superclass Pisces, subphylum Vertebrata and phylum Chordata. The mouth of the members of class Chondrichthyes is located ventrally and the teeth are modified placoid scales. They are arranged in multiple rows and point backwards, that is towards the interior of the mouth. This helps them keep a firm grip on their prey so it doesn’t escape