Final answer:
Statement B is true because the supply at Avery's node reduces to 150 when she falls sick and loses 30 hours of her work schedule.
Step-by-step explanation:
The correct statement is B. The supply at Avery’s node reduces to 150.
When Avery falls sick and loses 30 hours of her work schedule, the supply at her node (Avery’s node) will be affected. In the original problem, the supply at Avery’s node was 180, but with the loss of 30 hours, it will reduce to 150 hours.
Therefore, statement B is true.