Hint: The eggs are classified and divided on the basis of amount and distribution of yolk in them. Yolk is defined as the reserve food material in the cytoplasm of egg. It may be made up of phospholipids, proteins, lipids and carbohydrates. The process of formation and development of yolk and its deposition in egg is called vitellogenesis
On the basis of the presence of yolk the egg is majorly divided in four types. Nutritive substances are stored and remained within the cytoplasm of egg within the sort of yolk or deutoplasm.
This stored food is used by the embryo for its early development.
Now let us find solution from given options:
Alecithal - they are eggs that are without yolk. they do not perform as nutritive functions. e.g., human egg
Microlecithal - The eggs that have very little amount of yolk, e.g., sea urchin, starfish. These are also termed as oligolecithal eggs.
Mesolecithal - The eggs containing moderate amount of yolk, e.g., frog
Polylecithal -The eggs contain a very large amount of yolk, example, reptiles, birds.
Hence, the correct answer is option (A)
Note: Eggs of reptiles and birds which are insulated from the environment by albumen, membranes and shell. The calcareous shell present around the eggs of birds is mainly made of calcium carbonate (94%) and is secreted by the uterus (shell glands). Chalazae are the suspensory ligaments of the yolk in bird’s eggs.