“Mandatory” subjects of bargaining:a. must be negotiated if one
party raises the issue. b. must be negotiated until agreement is
reached if one party raises the issue. c. do not have to be
negotiated if one party raises the issue. d. mandates that a
federal mediator will resolve the differences between the parties
if they can’t reach agreement on one or more bargaining subjects.
e. mandates that a federal mediator must approve the agreement.