Which of the following statements is TRUE of arbitration of grievances under collective bargaining?

a. In determining whether there is a duty to arbitrate a dispute, the courts should examine the merits of the underlying grievance.

b. In labor contracts with an arbitration clause, if there is any doubt regarding the topics covered by the arbitration clause, then the topic should be considered as non-arbitrable.

c. The parties are not required to arbitrate a dispute that they have not agreed to submit to arbitration.

d. A court should enforce the decision of an arbitrator only after examining its correctness.