Which of the following refers to permanent improvements to property that may not be removed once ownership or occupancy ends?

The correct choice is fixtures, as these are defined as permanent improvements made to a property that become a part of the real estate. Fixtures are typically attached to the property in a way that removal would cause damage or require significant effort. Examples of fixtures include built-in cabinets, light fixtures, and plumbing installations. Since they are considered part of the property, they remain with the property when ownership transfers, which distinguishes them from other types of property.

Other terms like leaseholds refer to terms of occupancy rather than the concept of permanence or attachment to the property. Chattels represent movable items that can be taken away without affecting the property's structure, such as furniture or appliances, and fractional interest denotes a shared ownership stake in a property, focusing on the ownership aspect rather than improvements or attachments.