Final answer:
School-wide PBIS places emphasis on both preventing behavioral issues through antecedent interventions and enforcing school-wide disciplinary codes for a structured approach to behavior management.
Step-by-step explanation:
In school-wide Positive Behavioral Interventions and Supports (PBIS), emphasis is placed on both antecedent interventions and enforcing school-wide disciplinary codes. Antecedent interventions focus on preventing behavioral issues by modifying the environment and providing positive reinforcement for good behavior. Enforcement of school-wide disciplinary codes ensures that there are clear expectations and consequences for behavior, providing a structured approach to maintaining order and safety within the school. Therefore, the correct answer is C. both a and b.