Which, if any, of the following statements are untrue? Why

(a) A class must provide at least one constructor.

  True. If the programmer doesn't provide any constructor, the compiler will synthesise one default constructor.

(b) A default constructor is a constructor with an empty parameter list.

  Untrue. A constructor of which all parameters have default values also defines a default constructor.

(c) If there are no meaningful default values for a class, the class should not provide a default constructor.

  True. <!--- Need more consideration. --->

(d) If a class does not define a default constructor, the compiler generates one that initializes each data member to the default value of its associated type.

  Untrue. Only if a class does not define **any constructors**, will the compiler generate synthesised default constructor.