Luke and some of his co-workers are unhappy with the current working conditions at Brewcrew Industries. They have yet to start the unionization process but co-sign a letter to management expressing their frustrations and are all fired as a result. The firings are

Group of answer choices

A. allowed since they have yet to begin to unionize.

B. allowed since they did not attempt to bargain collectively.

C. not allowed due to free speech.

D. not allowed due to concerted activity.