Which fee simple estate can be ended by the grantor or their heirs upon the occurrence of a certain condition?

The correct choice is the fee simple on condition subsequent, which is a type of fee simple estate that is created with a specific condition attached. In this arrangement, if a certain event occurs or a condition is violated, the grantor or their heirs have the right to reclaim the property. This means that the original owner retains a future interest in the property, allowing them to take action if the specified condition is not met.

In contrast, a fee simple determinable automatically ends when a condition is met, reverting the property back to the grantor without the need for any action on their part. This distinction is significant because in a fee simple on condition subsequent, the grantor must actively choose to enforce their right to reclaim the property when the condition triggers.

The fee tail estate limits inheritance to specific heirs and does not have the same conditions attached, focusing instead on lineage. A leasehold, on the other hand, pertains to a temporary interest in property, providing use of the property for a set period but not conferring any ownership rights in the same way as a fee simple estate does.

Understanding these distinctions helps clarify why the fee simple on condition subsequent is the correct answer, as it directly relates to the grantor's right to end the estate upon