Flag question

What was the most significant and enduring feature of the Industrial Disputes Investigation Act $($IDI$)?$

Select one:

a$.$ Its short life.

b$.$ Its establishment of a labour board to deal with unfair labour practice complaints.

c$.$ Its voluntary nature.

d$.$ Its granting of collective bargaining rights to workers in certain industries.

e$.$ Its requirement of a conciliation board report and cooling off period before a strike or lockout could become legal.