All but Which One of the Following Actions Have Been

All but which one of the following actions have been deemed strikes?

A) unions' refusal to cross picket lines
B) a union's refusal to handle work that was the subject of a legal lockout between a different employer and a sister local
C) union- imposed overtime bans
D) a postal union's threat to order its members to stop verifying postage on letters
E) transit workers' union's order to its members to wear "civilian" clothing on the job