<prompt> Ring vaccination is -Given by a ring shaped machineGiven to produce a ring lesionGiven around 100 yards of a case detectedGiven around a mile of a case  <response>: Ans. is c i.e., Given around 100 yards of a case detected Ring immunization ring vaccination o It is a type of isolation, where vaccine is administered only to people in close contact with isolated infected patients. o This encircles the infected persons with a barrier of immune persons through whom the infection is unable to spread. o Method was used in Small pox o In noh america, ring immunization is being applied in measles control and eradication. Note : I am not sure about the distance, to which vaccination should be given option c or d. 