Which of the Following Statements About Prenatal Sensitive Periods with Respect

Which of the following statements about prenatal sensitive periods with respect to teratogens is true?

A) The fetal period is the time when serious defects are most likely to occur.
B) During the embryonic period, teratogens usually affect the growth of sensory organs, such as the eyes and ears.
C) In the period of the zygote, before implantation, teratogens rarely have any impact.
D) During the fetal period, teratogens have no impact on the developing organism.