$($Figure $4)$Consider the following UML diagram modelling an application that allows three types of registration for a conference. Registration, StudentRegistration and GuestRegistration represent standard, student and guest registrations respectively.

$1.$ Explain the relationship between Person and Registration. $[1]$

$2.$Write the definition $($no implementation$)$ of Registration. No pre$-$processor directives are required. $[5]$

$3.$ Write lines of code to create an instance of Registration.$[1]$

$4.$ Write the first line of the class definition $($classHead$)$ of StudentRegistration.$[1]$

$5.$ The cost of a student conference registration is half of what is returned by calculateFee$()$ in Registration. Implement the function calculateFee$()$ in StudentRegistration.$[3]$

$6.$ Explain the relationship between Registration and RegistrationList.$[2]$

$7.$ Write the first line of the class definition $($classHead$)$ of RegistrationList.$[2]$

$8.$ The function addRegistration$()$ takes a Registration$*$ as the input parameter. List all possible types of objects that can be added to a RegistrationList object. $[2]$

$9.$ Implement the function calculateTotalFee$()$ in RegistrationList, so that it adds and returns the total cost of all registrations in a RegistrationList object.