Question from the C++ - Fundamentals test

When there are no constructors in the class, C++ creates automatically one which initialize no attribute.

When there are no constructors in the class, C++ creates automatically one which calls the constructors of the attributes which are object and do nothing for the attributes with a primitive data type.

A default constructor is a constructor without parameters or with a default value for every parameters.

Instantiation with a default constructor does not need parenthesis (Rectangle r;).