Which of the Following Shows That a Baby Duckling's Instincts

Which of the following shows that a baby duckling's instincts depend to at least some degree on environmental cues?

A) Ducks always follow their mothers.
B) Ducks follow the first moving body they see.
C) Even if a duck's vocal cords are cut before it hatches, it will always prefer to follow its own mother.
D) Ducks will only follow other ducks.
E) Ducks made to hatch in a laboratory at night always become nocturnal.