Why is «hiya» appropriate in «al-ṭālibatu hiya al-nājiḥah»?

The Separating Pronoun (Ḍamīr al-Faṣl): Restriction, Emphasis and Predication

• Because nājiḥah is masculine plural
• Because the subject is feminine singular
• Because hiya must follow every subject
• Because hiya is a negative particle