Which revision uses a relative clause to combine the sentences?

Koalas are marsupials. They live in eucalyptus forests.

Responses

Koalas are marsupials living in eucalyptus forests.
Koalas are marsupials living in eucalyptus forests.

Koalas are marsupials that live in eucalyptus forests.
Koalas are marsupials that live in eucalyptus forests.

Koalas are marsupials though they live in eucalyptus forests.
Koalas are marsupials though they live in eucalyptus forests.

Koalas are marsupials and live in eucalyptus forests.

Koalas are marsupials that live in eucalyptus forests.