The key idea is how joint tenancy differs from tenancy in common in survivorship, the requirements to create the ownership, and how shares can be arranged. In a joint tenancy, there is a right of survivorship: when one owner dies, that deceased owner’s interest passes automatically to the surviving co-owners, not to the deceased owner’s heirs. In tenancy in common, there is no survivorship, so the deceased owner’s share goes to heirs or as provided by a will. Creating a joint tenancy also requires four unities: time, title, interest, and possession. All co-owners must acquire their interests at the same time, through the same instrument, with identical ownership rights, and they must all have a right to possess the whole property. Tenancy in common does not require all four unities, so co-owners can take title at different times, by different instruments, with different interests, yet still share possession. Finally, tenancy in common can accommodate unequal shares, while joint tenancy typically involves equal shares (absent a clear provision to the contrary). Since all these points can be true, the combined statement is the best description of how joint tenancy and tenancy in common differ.