Final answer:
All of the options provided (unexplained injuries, multiple bruises at different healing stages, and injuries inconsistent with the child's developmental level) are critical indicators of physical abuse.
Step-by-step explanation:
Considering the different indicators of physical abuse, all of the given options (A, B, and C) are considered critical. These include unexplained injuries that have no clear or believable explanation, multiple bruises in various stages of healing indicating repeated injuries over time, and injuries that are inconsistent with a child's age or developmental level, implying that the injuries could not have been self-inflicted or accidental based on their capabilities and knowledge.