Why is it advantageous for the embryos of reptiles and birds to produce uric acid instead of ammonia?

A)Uric acid is relatively nontoxic and won't harm the developing embryo as it is stored inside of the egg.Ammonia is far more toxic and could cause developmental problems if it was confined to the interior of an egg alongside of the embryo.
B)Uric acid will diffuse out of the shell whereas ammonia would be trapped inside of the shell with the developing embryo.
C)Uric acid can be recycled by the developing embryo and used as an alternative source of energy.Ammonia cannot be used as an alternative source of energy.
D)The uric acid can be broken down much easier than the ammonia by the excretory system of these animals.