laying eggs to reproduce having hollow, light-weight bones avoiding insects that taste bad having white feathers on the throat
I gave my students this multiple choice question: Which of the following involves a learned behavior?

Only one answer is correct among these 4 choices:
- laying eggs to reproduce
- having hollow, light-weight bones
- avoiding insects that taste bad
- having white feathers on the throat

Could you tell me which one is correct?

avoiding insects that taste bad