What employee right was recognized by the wagner act?

a earning a minimum wage
b joining labor unions
c receiving overtime pay
d working in smoke-free environments

B is the closest answer to your question, so B is the answer :)  

The best and most correct answer among the choices provided by the question is the second choice "joining labor unions"

The broad intention of the act, commonly known as the Wagner Act after Senator Robert R. Wagner of New York, was to guarantee employees “the right to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage.

I hope my answer has come to your help. God bless and have a nice day ahead!

Corruption i think