She never acknowledged WMD, why'd she perform it?
My guess would be Hopless and Just A Friend like she did with VEVO Presents and Target. Although I want KCMD too.
Realistic guesses:
Watch Me Do & Hopeless Romantic
Personally I want:
KCMD & Thank You (title track)
I'd love to see a live performance of WMD just to see what it's like, since a big part of the song is just she going "hey, heey, heeeeeeey!!!". It would be funny to see her do that.
WMD is the true album seller of "Thank You" though
According to trusted studies, Thank You would've sold 3M in the last 4 weeks if WMD wasn't the album opener. However, it turned 2.8M potential buyers off.