Whales being aquatic, is considered as mammal. They have blowhole that resembles to nose of mammals and they also feed their babies like mammals.
Mammals are warm blooded animals that gives birth to young ones. They have advanced reproduction and prenatal care for their babies.
The mammals have following characteristics:
As whale have mammary glands, they gives birth to young ones and feed milk to their babies, so, these are included under mammals.
Thus, the correct option is 1.
For more details regarding mammals, visit:
https://brainly.com/question/15326492