What does an immutable object ensure in terms of software stability?

An immutable object is one whose state cannot be modified after it has been created. This characteristic plays a crucial role in ensuring software stability. By preventing changes to its properties, an immutable object helps avoid unintended side effects that can occur when multiple parts of a program attempt to read or write to the same object.

In a scenario where an object is mutable, changes in one part of the code can inadvertently affect other parts that rely on the same object, leading to bugs that are difficult to trace. However, with immutable objects, once an object is instantiated, its state remains consistent throughout its lifecycle. This predictability simplifies debugging and reasoning about code, as developers can be assured that an object's properties will not change unexpectedly.

While the other options may relate to programming practices, they do not capture the fundamental aspect of immutability in ensuring stability due to the prevention of side effects. Frequent updates, code redundancy, and performance optimization are important considerations in software development, but they do not directly align with the stability benefits brought about by immutability.