Problem: You have a set of tasks that need to be completed. Each task has a duration and a deadline by which it must be finished. Your goal is to schedule these tasks in a way that maximizes the number of tasks completed while ensuring that no task is $.$completed after its deadline

:Tasks to be completed are

Task A: Duration $=2,$ Deadline $=4*$

Task B: Duration $=1,$ Deadline $=2*$

Task C: Duration $=3,$ Deadline $=6$

Task D: Duration $=2,$ Deadline $=8$

Define the variables, domains, and constraints of $.1.$the problem

$.$Find a solution for the problem $.2$