Which of the Following Is True of an Economic Strike

Which of the following is true of an economic strike?

A) It is a nonviolent work stoppage for the purpose of protesting an employer's commission of an unfair labor practice.
B) It is a protected activity and strikers are entitled to return to their jobs once the strike is over.
C) Employers are not allowed to fill economic strikers' jobs while the strike is taking place.
D) Since employers cannot permanently replace economic strikers, this strike is considered a potent weapon.