In the early nineteenth century, a french naturalist named Jean-Baptiste Lamarck developed a theory. He said that an organism passes on to its offspring the traits it acquires during its lifetime in response to the environment. For instance, Lamarck's theory explains why giraffes have long necks. It is because their shorter-necked ancestors spent their lives stretching to reach food. Which study would best test whether Lamarck's theory is valid?

A. determining if the children of body builders are more muscular than the children of people who do not lift weights.

B. Isolating a population of straight-winged fruit flies, allowing them to mate, and then observing the wing type of the offspring

C. exposing wheat seeds to extreme cold and then observing how well they grow in cold conditions

D. Crossing pea plants with different colored flowers and observing the colors of the flowers of their offspring