The possible answers are
a) It is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances.
b) It is a homogeneous mixture of mRNA, proteins, organelles, and other substances.
c) It does not contain substances that are important in directing development. These substances are supplied by the sperm.
d) It does not contain substances that are important in directing development. Development is directed solely by the surrounding cells.
e) It does not contain substances that are important in directing development. These substances are produced by the DNA of the fertilized zygote.
The correct answer is A.
The fertilized egg cell possesses a mixture of mRNA and proteins that guide the initial steps in the development of the embryo. These molecules are distributed unevenly in the fertilized egg cell, making the cell polar and causing an uneven production of proteins in different parts of the cell. This makes cells more and more different with each new division of the zygote.