The correct option is D Both A and B
Cleidoic eggs have a protective shell, and are laid out of water. The shell is porous to air, and may be flexible or calcareous (hard). The eggs contain all the food the embryo needs to develop into a hatchling. The significance of the cleidoic egg is that it enables reproduction out of, and often away from, water. It is a characteristic of birds and reptiles. Hence, option D is correct.