Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true? a. Careful monitoring of prothrombin time and aPTT time are necessary to avoid bleeding complications b. A level of serum fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding c. Recent (less than 10 days) major surgery is a contraindication to systemic but not regional fibrinolytic therapy d. A patient with a cerebrovascular event occurring less than two months ago can be treated with fibrinolytic therapy if head CT scan is normal