frighten away other types of birds mark the bird's territory against the same type of bird attract insects wake up other animals
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: When a bird sings, it is most likely singing in order to
Possibilities:
- frighten away other types of birds
- mark the bird's territory against the same type of bird
- attract insects
- wake up other animals

mark the bird's territory against the same type of bird