Which of the following is the correct sequence of prenatal development (starting with the earliest stage)?
a. Fertilization, Cleavage, Implantation, Gastrulation
b. Implantation, Fertilization, Gastrulation, Cleavage
c. Fertilization, Implantation, Cleavage, Gastrulation
d. Cleavage, Fertilization, Gastrulation, Implantation