$1\mathrm{.}1$ Write down the first line $($i$.$e$.$ the class header$)$ for a class to represent this window.$(1)$

$1\mathrm{.}2$ In general, what is the purpose of the QActionGroup class, and how could it be used to simplify the coding of this problem?$(3)$

$1\mathrm{.}3$ What Qt GUI classes would you use for creating this interface $($apart from the QInputDialog and QMessageBox classes that will be used for adding and deleting birthdays$)?$ Which of them would have to be declared as data members in the class definition, and which could be declared as local variables in the constructor? $(4)$

$1\mathrm{.}4$Consider the following definitions of the classes which are intended to be used with the GUI described above: