Protected Concerted Activities Under the NLRA, That Covers All Workers

Protected concerted activities under the NLRA, that covers all workers, unionized or not, include:

A) refusal to work because of unreasonable hazards
B) refusal to work in freezing conditions without protection
C) refusal to work due to conditions that endanger health
D) refusal to work in freezing conditions without protection and refusal to work due to conditions that endanger health
E) refusal to work in freezing conditions without protection and refusal to work due to conditions that endanger health and refusal to work because of unreasonable hazards