Final answer:
Constructors I and III are legal for the NamedPoint class. Constructor I relies on the default constructor of the superclass, while Constructor III uses the super keyword to explicitly call the superclass's constructor. Constructor II is illegal because it tries to set private fields directly.
Step-by-step explanation:
The student is asking which constructors would be legal for the NamedPoint class that extends the Point class. The legality of constructors in a Java class is determined by the correct use of the super keyword for calling a superclass's constructor and the proper setting of private fields.
Constructor I sets the name field only, assuming the superclass's no-argument constructor will be called by default to initialize x and y to zero. Constructor III is also correct because it explicitly calls the superclass's constructor with arguments using the super keyword and sets the name field.
Constructor II, however, attempts to set the x and y fields directly, which is not allowed since these fields are declared private in the superclass.
Therefore, the legal constructors are I and III only.