Laboratory monitoring of coagulation and anticoagulation includes testing of platelet function. Which of the following statements is/are true concerning tests of platelet function? a. A platelet count of 50,000/µL or more usually ensures hemostasis b. Bleeding time assays assessibility of platelets to perform hemostatic plugs and is determined from a sample of blood drawn in an EDTA coated test tube c. Aspirin therapy can be associated with a bleeding time in the range of 8–15 minutes d. Tests of platelet aggregation should be part of the standard preoperative evaluation of patients using aspirin