What type of ownership refers to undivided ownership of an estate exclusive from other owners?

The correct choice refers to "severalty," which denotes a type of ownership where a single individual or entity holds full and exclusive legal rights over a property without any co-owners. This form of ownership contrasts sharply with joint tenancy and tenancy in common, where multiple individuals share ownership rights and interests in the property. In severalty, the owner has complete control over the property, allowing for decisions related to its use, management, and eventual sale to be made unilaterally.

Community property is also distinctly different, as it pertains to property ownership in marriage where both spouses share ownership equally. Therefore, severalty stands out as the only type of ownership that guarantees undivided ownership exclusive from other owners, providing the owner with total autonomy over the estate.