The characteristics of class Reptilia are?

• A. Marine animals with cartilaginous endoskeleton, body covered with placoid scales
• B. Fresh water animals with bony endoskeleton, air-bladder to regulate buoyancy
• C. Body covered with moist skin which is devoid of scales, the ear is represented by a tympanum, alimentary canal, urinary and reproductive tracts open into a common cloaca
• D. Body covered with dry and cornified skin, scales over the body are epidermal, they do not have external ears