In Coppage V

In Coppage v. Kansas (1912) , the Supreme Court held that

A) all employers were required to offer employees the option of joining a union.
B) an employer's right to require that employees sign "yellow-dog contracts" was protected by the 14^th Amendment.
C) "yellow-dog" contracts were illegal for any business engaged in interstate commerce.
D) using federal troops to break strikes was a legitimate use of police power.
E) All of the above.