Answer:
Herself
Step-by-step explanation:
The word "herself" in this sentence is an example of a reflexive pronoun. A reflexive pronoun is a pronoun that is used as a direct object (the person, place, thing receiving the action of the verb) when the object is the same as the subject of the verb. In this case, the person doing the action (stopping) is the same person that is receiving it. Therefore, we use the pronoun "herself."