Distinguishing Simple Subject and Predicate

“Before performing, she feels increasingly nervous”.

Definition of a Complete Sentence
A complete sentence must have a subject and predicate and express a complete idea.
You can write a complete sentence with just two words in it: 1) a verb that expresses an action or a
state of being, and 2) a noun that performs the action. Most sentences contain additional words to give more information about the subject and predicate.

Examples:
People applauded.
The people in the audience applauded loudly at the end.

Which part of this complete sentence could also stand alone as a complete sentence?

A) Before performing.
B) She feels.
C) Increasingly nervous.