Why was the union certification process established by the National Labor Relations Act in $1935$ initially a great success? $($Check all that apply.$)$

Multiple select question.

Firing union supporters was deemed illegal.

Unions could do away with a variety of methods used to determine majority status such as authorization cards and union membership applications.

Workers were provided the right to strike for recognition.

Workers could petition the National Labor Relations Board for a democratic determination of whether a majority of workers favored unionizing.