The method for calculating earned value should be agreed to before the work begins and it is best to keep the earned value calculation method as:

Thanks for the invite.

Of course it is B - Milestone. Milestone has no time and cost attached to it.

My oppinion is that B is right answer.

Thanks for your invitation. Option- B.

I think milestone is good answer. Thank you.

My answer is option (B) -----------

Thanks for the invitation. I would like to select option B.