In which of these types of co-ownership can property be owned in unequal portions?

Tenancy by the entirety is a form of co-ownership exclusively available to married couples, where each spouse owns an equal and undivided interest in the property. This type of ownership does not allow for unequal portions since both parties must hold identical shares, thus reinforcing unity in ownership.

A sole proprietorship refers to a business structure where a single individual owns and operates the business. It is not a form of property co-ownership, and thus does not apply to the question regarding ownership shares. There are no co-owners involved, so the concept of unequal portions is irrelevant.

Joint tenancy involves two or more individuals owning property together with equal shares and the right of survivorship. This means that each co-owner has an equal interest in the property, and upon the death of one owner, their share automatically passes to the surviving owner(s). Therefore, joint tenancy does not accommodate unequal portions of ownership.