What Are (Is)the Main Factor(s)causing Differences Between the Chick Hatch

What are (is) the main factor(s) causing differences between the chick hatch weight and the weight of the egg when it is laid?

A) The only factor that causes the chick to weigh less than the egg when it is laid is the removal of the shell.
B) Not only does the hatchling have no shell,but it has lost some of its mass (weight) to the air during development.
C) During development,the chick gains new parts so the weight increases.
D) Egg weight at oviposition includes a lot of water that evaporates during development.