Which of the following rows correctly identifies the stage in development and the embryonic age most sensitive to teratogens, respectively? Select One: a). Stage: fetus, Embryonic age: 9 to 16 weeks, b). Stage: embryo Embryonic 6 to 12 weeks. c). Stage: fetus, Embryonic age 9 o 40 weeks d). Stage: embryo, Embryonic age: o to 9 weeks. 

I think its b teratogens happen during the first trimester and that happens in the embryoic development. but im not sure