Aperiod during which the embryo of a seed is alive but not growing is
a. dispersal.
b. fertilization.
c. germination.
d. dormancy.

The answer is d. dormancy.

Dormancy is physiological condition during which growth and development are temporarily stopped. The aim of this condition is to preserve energy by minimizing metabolic activity, usually because of inadequate environmental conditions. 
Dispersal refers to movement of individuals from one site to another. Fertilization means a fusion of gametes to develop a new organism.
Germination is a process of growing plant from a seed.