Final answer:
Vicarious Liability: Employers are held responsible for the actions of their employees performed within the scope of employment.
Step-by-step explanation:
The principle of liability that states that Maria will be responsible if Bob acted within the scope of employment is Vicarious Liability. Vicarious Liability is a legal principle that holds employers responsible for the actions of their employees while they are performing their job duties. If an employee, such as Bob, is driving Maria's Bakery delivery truck and gets into an accident, Maria could be held liable for any damages or injuries caused by Bob within the scope of his employment.