The correct option is B 8 weeks
Deworming is the giving of an antihelminthic drug to a human or animal to rid them of helminths parasites, such as roundworms, flukes and tapeworms. Deworming is stressful on chickens, so it should be avoided under six weeks of age, during the winter, or during the fall molt. So it is usually done at the age of 8 weeks. Hence, option B is correct.