Which statement correctly describes getter properties?

Getter properties are designed primarily to retrieve and return the value of an object's attribute without modifying that value. This means that when a getter is called, it simply provides access to the underlying data and does not perform any operations that affect the state of that data. The essence of a getter is to maintain encapsulation by allowing controlled access to private or protected properties, ensuring that the integrity of the data is preserved.

In contrast, other options do not accurately reflect the purpose of getter properties. They do not modify data, as that is the role of setters. Getters do not take input parameters; they are invoked without any arguments, simply returning the current value of the property. Additionally, getters are not responsible for storing data; that function is fulfilled by the underlying data storage mechanism or constructors of the class. Therefore, the assertion that they can only return a value and should not alter data is a fundamental characteristic of getter properties.