which sentence incudes an indipendent clause?

The package was heavy.
It was a fancy hat!
She smiled as she opened the package.
Today is her 6th birthday.

Which option means " a group of words that has a subject and a predicate, and is a complete sentence?"

dependent cause.
independent clause.
prepositional phrase.
noun phrase.

independent clause.

The sentence "She smiled as she opened the package." includes an independent clause.

The package was heavy.