Link verbs

What is the linking verb in the sentence:

Trentyn and Corbin are outside playing hide and seek.

• Trentyn

• outside

• are

• seek

John is under the table reading a book.

• John

• is

• under

• table

The flower smells beautiful.

• smells

• beautiful

• flower

• the

I am tired after playing soccer all night.

• I

• after

• am

• night