Why Allah? Why Islam? Why Muhammad?

You may have heard about the 3 questions that every Muslim shall be asked in their grave:

Who is your God?
Who is your Rasul?
What is your Deen?

Of course, we know the answers to these questions, any Muslim would. Then what is this lectureshop about and why do I need to attend this?
Well, have you ever been in a super-stressful situation and not been able to answer a simple question..? Say someone pulled a gun on you and asked you your name, would you be able to give a coherent answer right away? 

Depending on our actions in this finite world, our graves may not be the most pleasant places to transition into, and neither will our questioners (angels of Allah) be. Should our answers be wrong, it is said that the angels inflict a beating upon the person. And that will not help us any.