Alienware m15 R2 : which electric alimentation please ?

Hello

I want to buy an Alienware m15 R2. 

So I put it in basket , then 3 kinds of electric alimentation are proposed . With 3 different voltages ?

1) Do I need to buy one also , isn't the power alimentation included with the computer ? I wouldn't want to receive 2 of them

2) Then if I have to buy one : Which voltage should I select ? I live in France .

There is nobody answering in help chat ... I try during opened hours though ...

Thanks for helping me with this .