This should be 2. collaborated or is there a catch I am not seeing?

rootmachine

Eliza ___________ seamlessly with her peers from other classes to come up with a stunning performance.

Came up with this for my fifth graders. What do you think the answer is?

Stacker Saloon

saloon

Eliza ___________ seamlessly with her peers from other classes to come up with a stunning performance.

1) concentrated
2) collaborated
3) corroborated
4) commemorated

Came up with this for my fifth graders. What do you think the answer is? 