Answer:
a. Frankpledge System.
Step-by-step explanation:
The Frankpledge System was one type of suretyship prevalent in England, especially during the early and high Middle Ages. This system's primary policy is the sharing of responsibility among the people connected. King William instituted this system after the 1066 Norman conquest as a form of policing the community and making sure of the power structure.
In simple terms, it means that the responsibility of ensuring the safety of the society rests on the members of the society who are made responsible for the way their peers act. This mutual responsibility among the members of society means that everyone is responsible and will also be held responsible for the actions of others.