I'll have done it ... the time you arrive. a) –, b) at, c) in, d) by ​

I'll have done it at the time you arrive.

I'll have done it by the time you arrive.

-hi. i have a birthday next week, and i woud arrange a party.

-oh! it's a good idea.

-can you help me with it?

-yes of cause. how do you want decorate your flat?

-actually i dont may be some

- i'll buy them. and who do you want to invite?

-my close friends only. and you of cause!

-ok. what about snaks?

-my mom wants to cook some snaks like and ill buy a cake.

-it wiil be a great party, i think!

-i want to belive in that. ill call you. bye!

-bye!