This class is in three parts: C3a  Use by a single person or a family (a couple whether married or not, a person related to one another with members of the family of one of the couple to be treated as members of the family of the other), an employer and certain domestic employees (such as an au pair, nanny, nurse, governess, servant, chauffeur, gardener, secretary and personal assistant), a carer and the person receiving the care and a foster parent and foster child. There are no permitted changes. C3b  Up to six people living together as a single household and receiving care e.g. supported housing schemes such as those for people with learning disabilities or mental health problems. There are no permitted changes. C3c – Up to six people living together as a single household. This allows for those groups that do not fall within the C4 HMO definition, e.g. a homeowner who is living with a lodger. There are no permitted changes.