Which of the Following Is Correct with Regard to the Issue

Which of the following is correct with regard to the issue of strikes?

A) Sometimes unions are not permitted to strike.
B) In Nova Scotia,strikes by health-care workers are allowed,but in Alberta hospital workers cannot go on strike.
C) Canada had the highest number of days lost to strikes per thousand employees during the period 1981-2003.
D) During a strike,workers cannot launch a boycott.
E) All of these.